Krishnananda Chattopadhyay , Ph.D.

Chief Scientist & Head, Structural Biology & Bioinformatics Division
Structural Biology & Bioinformatics

Research Focus

Fluorescence correlation spectroscopy, protein folding, intrinsically disordered proteins, stability and aggregation of proteins

Research Interest

We use single molecules spectroscopy to study the folding, dynamics and aggregation of protein molecules in aqueous solution and inside live neuroblastoma cells. We have developed, for the first time, the applications of fluorescence correlation spectroscopy (FCS) to study microsecond fluctuations in protein molecules at single molecular resolution. Our group showed that a protein fluctuates between conformers of different radii, and these fluctuations (and not the structure alone) play key roles in defining its functions, folding and aggregation. Using alpha synuclein, a protein with strong implications in Parkinson’s disease (PD), we showed that these initial contacts can be correlated with subsequent oligomer formation and eventual formation of amyloid fibrils. Our work critically emphasizes on the importance of the early fluctuations towards developing small molecule aggregation inhibitors. Subsequently, our group used small molecules to coat magnetite nanoparticles for efficient inhibition of the early events of alpha synuclein aggregation. Using cytochrome c, we showed that these fluctuations affect the secondary function of apoptotic regulations of the protein. A highlight of this paper was written by a senior editor of Nature magazine for the June 2015 issue of Nature Chemical Biology.




  • 1991-1994: MSc in Chemistry, The University of Burdwan, Burdwan, India, first class.
  • 1988-1991: BSc in Chemistry, Hooghly Mohsin College, The University of Burdwan, India, first class.
  • 1994-1999: PhD in Chemical Sciences, Tata Institute of Fundamental Research (TIFR), Mumbai


Employment History:

  • Sep 2019-present: Chief Scientist, Structural Biology and Bioinformatics Division, CSIR-Indian Institute of Chemical Biology
  • Feb 2017 to Current: Head, Structural Biology and Bioinformatics Division, CSIR-Indian Institute of Chemical Biology
  • Sep 2014 to Sep 2019: Senior Principal Scientist, Structural Biology and Bioinformatics Division, CSIR-Indian Institute of Chemical Biology, Professor in Chemistry and Biology, Academy of Scientific and Innovative Research 
  • Jun 2019 onwards: Head, Library and Documentation Division, CSIR-Indian Institute of Chemical Biology
  • Sep 2010 to Sep 2014: Principal Scientist, Structural Biology and Bioinformatics Division, CSIR- Indian Institute of Chemical Biology, Kolkata 700032
  • Associate Professor in Chemistry and Biology, Academy of Scientific and Innovative Research
  • Dec 2006-2010: Senior Scientist, Protein Folding and Dynamics Laboratory, Structural Biology and Bioinformatics Division, Indian Institute of Chemical Biology, Kolkata 700032
  • 2005 – 2006: Senior Scientist, Formulation Development and Product Enhancement, Pfizer Global Biologics, St. Louis, MO 63017, USA
  • 2000-2005: Post doctoral research , Advisor: Dr. Carl Frieden, Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110

Honours & Awards

  • 2019: Fellow of West Bengal Academy of Science and Technology
  • 2019: Fellow of Royal Society of Chemistry
  • 2015; American Chemical Society Membership Award
  • 2010: Visiting Faculty, The Department of Physics, University of Illinois at Urbana Champaign, IL, USA
  • 2009: Indo-US Science and Technology Forum Research Fellowship
  • 2006: Pfizer performance recognition award


Patents & Publications



  1. Das, B; Roychowdhury, S; Mohanty, P; Rizuan, A; Chakraborty, J.; Mittal, J; & Chattopadhyay, K* (2022) A Zndependent structural transition of SOD1 modulates its ability to undergo phase separation, EMBO Journal,
  2. Sanyal, D; Banerjee, S.; Bej, A; Roy Chowdhury,V; Uversky, VN; Chowdhury, S. & Chattopadhyay K* (2022) An integrated understanding of the evolutionary and structural features of the SARS-CoV-2 spike receptor binding domain (RBD), International Journal of Biological Macromolecules,
  3. Sannigrahi, A; Chattopadhyay, K* (2022) Pore formation by pore forming membrane proteins towards infections, Advances in protein chemistry and structural biology, 12, 79-111          
  4. Mandal, N; Chattopadhyay, K*; Sannigrahi, A (2022) Studying protein-folding dynamics using single-molecule fluorescence methods, Advances in Protein Molecular and Structural Biology Methods, 225-236, Academic Press
  5. Mahapatra, A; Mandal, A & Chattopadhyay, K* (2021) Cholesterol in Synaptic Vesicle Membranes Regulates the Vesicle-Binding, Function, and Aggregation of α-Synuclein. Journal of Physical Chemistry B (American Chemical Society), DOI: (Front Cover)
  6. Chakraborty, R.; Dey, S.; Sil, P., Paul, S. S.; Bhattacharya, D.; Bhunia, A.; Sengupta, J.; Chattopadhyay, K*. (2021) Conformational distortion in a fibril-forming oligomer arrests alpha-Synuclein fibrillation and minimizes its toxic effects; Communications Biology (Springer Nature) ; DOI:10.1038/s42003-021-02026-z
  7. Sannigrahi, Achinta; Chowdhury, Sourav; Das, Bidisha; Banerjee, Amrita; Halder, Animesh; Saleem, Mohammed; Naganathan, Athi N; Karmakar, Sanat; Chattopadhyay, K* (2021) The metal cofactor zinc and interacting membranes modulate SOD1 conformation-aggregation landscape in an in vitro ALS Mode, eLife; DOI:, Highlights in the journal:, Highlights in other scientific blogs:
  8. Chattopadhyay K* (2021) Probing the influence of mutations on FUS condensates, one molecule at a time; Communications Biology (Springer Nature) DOI:
  9. Bandyopadhyay, A; Sannigrahi, A; & Chattopadhyay K* (2021) Membrane composition and lipid to protein ratio modulate amyloid kinetics of yeast prion protein; RSC Chemical Biology DOI: 10.1039/d0cb00203h
  10. Mahapatra, A; Sarkar, S; Biswas, SC; & Chattopadhyay K* (2020) Modulation of α-Synuclein Fibrillation by Ultrasmall and Biocompatible Gold Nanoclusters; ACS Chemical Neuroscience DOI:
  11. Mandal, N; De, N; Jana, P; Sannigrahi, A; & Chattopadhyay K* (2020) Correlation between CNS Tuberculosis and the COVID-19 Pandemic: The Neurological and Therapeutic Insights; ACS Chemical Neuroscience DOI:
  12. Sannigrahi, A; De, N; & Chattopadhyay K* (2020) The bright and dark sides of protein conformational switches and the unifying forces of infections; Communications Biology (Springer Nature), DOI:
  13. Kulsi, G; Sannigrahi, A; Mishra, S; Saha, KD; Datta, S; Chattopadhyay, P; & Chattopadhyay K* (2020) A Novel Cyclic Mobile Transporter Can Induce Apoptosis by Facilitating Chloride Anion Transport into CellsACS Omega; DOI: 
  14. Ghosh, G; Sakshi, Swain, BC; Chakraborty, R; Tripathy, U; & Chattopadhyay K* (2020) A Novel Tool to Investigate the Early and Late Stages of α-Synuclein AggregationACS Chemical Neuroscience DOI: (Highlights in Telengana Today:
  15. Halder, A; Sannigrahi, A; De, N; Chattopadhyay K*, S Karmakar (2020) Kinetoplastid membrane protein 11 induces pores in anionic phospholipid membranes: Effect of cholesterol,Langmuir 36, 3522
  16. Goswami, A; Mukherjee, K; Mazumder, A; Ganguly, S; Mukherjee, I; Chakrabarti, S; Roy, S; Sundar, S; Chattopadhyay K; & Bhattacharyya, SN (2000) MicroRNA exporter HuR clears the internalized pathogens by promoting proinflammatory response in infected macrophages,EMBO Molecular Medicine 12, e11011
  17. Saha, S; Sannigrahi, A; Chattopadhyay, K; & Chowdhury, J (2020) Interaction of KMP-11 and its mutants with ionic liquid choline dihydrogen phosphate: Multispectroscopic studies aided by docking and molecular dynamics simulations, Journal of Molecular Liquids 301, 112475
  18. Chowdhury, S; Sanyal, D; Sen, S; Uversky, VN; Maulik, U & Chattopadhyay K* (2019) Biomolecules 9, 826
  19. Basak, S; Sengupta, S & Chattopadhyay K* (2019) Understanding biochemical processes in the presence of sub-diffusive behavior of biomolecules in solution and living cells, Biophysical Reviews 11, 851 (Invited Review Article)
  20. Mahapatra, A, Sarkar, S., Biswas, SC, & Chattopadhyay K* (2019) An aminoglycoside antibiotic inhibits both lipid-induced and solution-phase fibrillation of α-Synuclein in vitro, Chemical Communication 55, 11052 (Highlights in Nature India,
  21. Sannigrahi A, Nandi I, Chall S, Jawed JJ, Halder A, Majumdar S, Karmakar S, Chattopadhyay K*, (2019) Conformational switch driven membrane pore formation by Mycobacterium secretory protein MPT63 induces macrophage cell deathACS Chemical Biology, (DOI
  22. Chowdhury S, Sen S, Banerjee A, Uversky VN, Maulik U & Chattopadhyay K* (2019) Network mapping of the conformational heterogeneity of SOD1 by deploying statistical cluster analysis of FTIR spectra, Cellular and Molecular Life Sciences, 1-10 (DOI
  23. Sannigrahi A, Mullick D, Sanyal D, Sen S, Maulik, U &Chattopadhyay K* (2019) Effect of ergosterol on the binding of KMP-11 with phospholipid membranes: implications in leishmaniasis, ACS Omega 4, 5155
  24. Som SC, Sannigrahi A, Nandi M, Mishra VK, De P, Chattopadhyay K… (2019) A novel PEGylated block copolymer in new age therapeutics for Alzheimer’s disease Molecular Neurobiology (DOI
  25. Chakraborty R, Chattopadhyay, K* (2019) Cryo-Electron Microscopy Uncovers Key Residues within the Core of Alpha-Synuclein Fibrils, ACS Chemical Neuroscience 10, 1135.
  26. Sen S, Dey, A, Chowdhury, S, Maulik, U, Chattopadhyay, K (2019) Understanding the evolutionary trend of intrinsically structural disorders in cancer relevant proteins as probed by Shannon entropy scoring and structure network analysis , BMC Bioinformatics 19, 549.
  27. Chatterjee, S., Ghosh, S., Mishra, S., Banerji, B., Saha, K.D, & Chattopadhyay K* (2019) Efficient detection of early events of alpha synuclein aggregation using a cysteine specific hybrid scaffold, Biochemistry, 58, 1109
  28. Hazra S., Bodhak, C., Chowdhury S., Sanyal D, Mandal, S. Chattopadhyay K, Pramanik, A. (2019) A novel tryptamine-appended rhodamine-based chemosensor for selective detection of Hg2+ present in aqueous medium and its biological applications, Analytical and Bioanalytical Chemistry (Cover)
  29. Ghosh S., Mahapatra A, Chattopadhyay, K* (2019) Modulation of Alpha-Synuclein Aggregation by Cytochrome c Binding and Hetero-di-Tyrosine Adduct Formation, ACS Chemical Neuroscience, 10, 1300
  30. Chakraborty, R., Sahoo, S., Halder, N., Rath, H., Chattopadhyay, K*. (2018) Conformational-Switch Based Strategy Triggered by [18] π Heteroannulenes toward Reduction of Alpha Synuclein Oligomer Toxicity, ACS Chemical Neuroscience 10, 573
  31. Mukherjee S, Hazra, S., Chaowdhury, S., Chattopadhyay, K. .. (2018) A novel pyrrole fused coumarin based highly sensitive and selective fluorescence chemosensor for detection of Cu2+ ions and applications towards live cell imaging, Journal of Photochemistry and Photobiology A: Chemistry 364, 635-644
  32. Tripathi T. & Chattopadhyay, K* (2018) Interaction of α-Synuclein with ATP Synthase: Switching Role from Physiological to Pathological, ACS Chemical Neuroscience 10 (1), 16-17
  33. Nandi I., Chall, S., Chowdhury, S. Mitra, T., Roy SS, Chattopadhyay, K*. (2018) Protein Fibril-Templated Biomimetic Synthesis of Highly Fluorescent Gold Nanoclusters and Their Applications in Cysteine Sensing, ACS Omega 3 (7), 7703-7714
  34. Ghosh, S., Kundu, A. & Chattopadhyay, K* (2018) Small Molecules Attenuate the Interplay between Conformational Fluctuations, Early Oligomerization and Amyloidosis of Alpha Synuclein, Scientific Reports 8(1) 5481 (Highlights in The Hindu, Jun 03, 2018:; The Hindu BusinessLine, May 30, 2018;; Rajya Sabha TV Aug 11, 2018;
  35. Sarkar-Banerjee, S., Goyal, S., Gao, N. Mack, J. Thompson, Dunlap, D., Chattopadhyay, K*, Finzi, L* (2018) Specifically bound lambda repressor dimers promote adjacent non-specific binding, Plos One 13 (4), e0194930
  36. Sannigrahi A., Chall, S., Jawed JJ., Kundu, A., Majumdar, S., &Chattopadhyay, K*., Nanoparticle Induced Conformational Switch Between α-Helix and β-Sheet Attenuates Immunogenic Response of MPT63,, Langmuir 34 (30), 8807-8817 (Highlights in The Hindu Jul 29, 2018; The Times of India, Aug 11, 2018;    researchers-develop-molecule-for-tb-vaccine/articleshow/65361922.cms)
  37. Saha, B., Chowdhury, S., Sanyal, D., Chattopadhyay, K, Suresh Kumar, G. (2018) Comparative Study of Toluidine Blue O and Methylene Blue Binding to Lysozyme and Their Inhibitory Effects on Protein Aggregation, ACS Omega 3 (3), 2588-2601.
  38. Singharoy, D., Chowdhury, S., Mati, SS, Ghosh, S., Chattopadhyay K*, Bhattacharya, SC* (2017) Photoinduced Electron Transfer Switching Mechanism of a Naphthalimide Derivative with its Solvatochromic Behaviour: An Experimental and Theoretical Study with..., Chemistry-A European Journal 23 (65), 16516-16524
  39. Chall, S., Matti, SS, Das, I., Kundu, A. & Chattopadhyay, K* (2017) Understanding the Effect of Single Cysteine Mutations on Gold Nanoclusters as Studied by Spectroscopy and Density Functional Theory Modeling, Langmuir 33(43) 12120-12129.
  40. Kundu A., Kundu, S. &Chattopadhyay, K*. (2017) The presence of non-native helical structure in the unfolding of a beta sheet protein MPT63, Protein Science 26(3) 536-549.
  41. Sannigrahi A., Maity, P., Karmakar, S. & Chattopadhyay, K*. (2017) Interaction of KMP-11 with Phospholipid Membranes and Its Implications in Leishmaniasis: Effects of Single Tryptophan Mutations and Cholesterol, The Journal of Physical Chemistry B 121, 1824
  42. Banerjee-Sarkar, S., Chowdhury, S., Paul, S.S., Dutta, D., Ghosh, A., & Chattopadhyay, K*. (2016) The Non-native Helical Intermediate State May Accumulate at Low pH in the Folding and Aggregation Landscape of the Intestinal Fatty Acid Binding Protein, Biochemistry 55 (32) 4457-4468.
  43. Paul, S. S., Sil, P., Chakraborty, R., Haldar, S., & Chattopadhyay, K*. (2016) Molecular crowding affects the conformational fluctuations, peroxidase activity and folding landscape of yeast cytochrome c, Biochemistry 55, 2332-2343.
  44. Kundu, A, Ghosh, S., & Chattopadhyay, K*. (2016) The effect of small molecules on early and late events of alpha synuclein aggregation in solution and inside living cells, Biophysical J. 110, 533a.
  45. Paul, S.S., Sil, P., Haldar, S., Mitra, S. & Chattopadhyay, K*. (2015) Subtle change in the charge distribution of surface residues may affect the secondary functions of cytochrome c, J. Biol. Chem. 290, 14476-14490. (Highlights: Shape your duty,  Eggleston AK et al Nature Chemical Biology
  46. Mukherjee, M., Ghosh, R., Chattopadhyay, K*. & Ghosh, S. (2015) pH-induced structural change of a multi-tryptophan protein MPT63 with immunoglobulin-like fold:identification of perturbed tryptophan residue/residues, Journal of Biomolecular Structure and Dynamics DOI:10.1080/07391102.2014.992043
  47. Haldar, S., Sil, P., Thangamuniyandi, M., & Chattopadhyay K*. (2014) Conversion of amyloid fibrils of cytochrome c into matured nano rods through a honeycomb morphology, Langmuir 31, 4213-4223.
  48. Joshi, N., Basak, S., Kundu, S., De, G., Mukhopadhyay, A., & Chattopadhyay, K*. (2014) The attenuation of the early events of alpha-synuclein aggregation: A fluorescence correlation spectroscopy and laser scanning microscopy study in the presence of surface coated Fe3O4 nanoparticles, Langmuir 31, 1469-1478.
  49. Basak, S., Prasad, G.V., Varkey, J. & Chattopadhyay, K*. (2014) Early SDS induced collapse of alpha synuclein correlates with its amyloid formation, ACS Chemical Neuroscience 6, 239-246 (Highlights in Journal Web Page).
  50. Parmanik, B., Kundu, A., Chattopadhyay, K*.,& Patra, A*. (2014) Study of binding interactions between MPT63 protein and Au nanocluster, RSC Advances 4, 35059-35066.
  51. Basak, S. & Chattopadhyay, K*. (2014) Studies of protein folding and dynamics using single molecule fluorescence spectroscopy, Physical Chemistry Chemical Physics, DOI: 10.1039/C3CP55219E. (invited review article)
  52. Sarkar, S. & Chattopadhyay, K*. (2014) Studies of early events of folding of a predominately beta sheet protein using fluorescence correlation spectroscopy and other biophysical methods, Biochemistry 53, 1393-1402
  53. Lahiri, S., Banerjee, S., Dutta, T., Sengupta, S., Dey, S., Roy, R., Sengupta, D., Chattopadhyay, K. & Ghosh, A. K*. (2014) Enzymatic and regulatory attributes of Trehalose6Phosphate Phosphatase from Candida utilis and its role during thermal stress, Journal of Cellular Physiology, DOI: 10.1002/jcp.24562.
  54. Basak S., Chattopadhyay K*. (2013) Fluorescence Correlation Spectroscopy Study on the Effects of the Shape and Size of a Protein on Its Diffusion Inside a Crowded Environment, Langmuir 29, 14709-14717.
  55. Sharma, S., Sarkar, S., Paul, S.S., Roy, S. & Chattopadhyay, K*. (2013) A small molecule chemical chaperone optimizes its unfolded state contraction and denaturant like properties, Sci. Rep. 3, 3525; DOI:10.1038/srep03525, Nature Publishing Group
  56. Joshi N., Mukhopadhyay, A., Basak, S., De, G., Chattopadhyay, K.* (2013) Surface Coating Rescues Proteins from Magnetite Nanoparticle Induced Damage,, Part. Part. Syst. Charact. 30, 683–694 (Journal Front Cover Article).
  57. Sharma, S., Pathak, N., Chattopadhyay, K*. (2012) Osmolyte induced stabilization of protein molecules: A Brief Review,, Journal of Proteins and Proteomics 3(2):129-139.
  58. Ghosh R., Mukherjee M., Chattopadhyay K*, Ghosh S*. (2012) Unusual optical resolution of all four tryptophan residues in MPT63 protein by phosphorescence spectroscopy: assignment and significance, J Phys Chem B 116(41):12489-500.
  59. Haldar, S., & Chattopadhyay, K*. (2012) The interconnection of salt induced hydrophobic compaction and secondary structure formation depends on solution conditions: revisiting early events of protein folding at single molecule resolution, Journal of Biological Chemistry 2012, 287,11546–11555.
  60. Haldar, S., Paul, S. S., Joshi, N., Dasgupta, A., Chattopadhyay, K*. (2012) The Presence of the Iron-Sulfur Motif Is Important for the Conformational Stability of the Antiviral Protein, Viperin, Plos One Volume 7 Issue 2  e31797.
  61. Lahiri, S., Basu, A., Sengupta, S., Banerjee, S., Dutta, T., Soren, D., Chattopadhyay, K., Ghosh, A. K*. 2012 Purification and characterization of a trehalase–invertase enzyme with dual activity from Candida utilis, Archives of Biochemistry and Biophysics 522, 90–99.
  62. Mukhopadhyay, A., Joshi, N., Chattopadhyay, K*., De, G*. (2011) A facile synthesis of PEG-coated magnetite (Fe3O4) nanoparticles and their prevention of the reduction of cytochrome c, ACS Appl Mater Interfaces 2012, 4, 142-9.
  63. Sen, T., Mandal, S., Haldar, S., Chattopadhyay, K*., and Patra, A*., (2011) , J. Phys. Chem. C 115 (49), 24037–24044.
  64. Haldar, S., & Chattopadhyay, K*. (2011) Effects of arginine and other solution additives on the self-association of different surfactants: an investigation at single molecule resolution, Langmuir 27, 5842-5849
  65. Mukhopadhyay, A., Basak, S., Das, JK., Chattopadhyay, K. & De, G*. (2010) Ag-TiO2 nanoparticle co-doped SiO2 films on ZrO2 barrier-coated glass substrates with antibacterial activity in ambient condition, ACS Appl. Mater. Interfaces 9, 2540-6.
  66. Haldar, S, Mitra, S. & Chattopadhyay, K* (2010) The role of the protein stabilizers on the conformations of the unfolded states and its early folding kinetics: An investigation at single molecular resolution, J. Biol. Chem. 285, 25314-23.
  67. Ghosh, R., Sharma, S. & Chattopadhyay, K*. (2009) Effect of Arginine on Protein Aggregation Studied by Fluorescence Correlation Spectroscopy and Other Biophysical Methods, Biochemistry 48 (5), 1135 – 1143.
  68. Chattopadhyay, K. & Frieden, C. (2006) Steady State and Time-resolved fluorescence studies of the intestinal fatty acid binding proteins, Proteins 63, 327-335.
  69. Chattopadhyay, K., Elson, E. L., & Frieden, C.  (2005) Measurements of microsecond dynamics of the unfolded state by using fluorescence methods, Proc. Natl. Acad. Sci (USA) 102, 2385-2389 (Faculty of 1000 Recommended).
  70. Chattopadhyay, K., Saffarian, S., Elson, E. L., & Frieden, C. (2005) Measuring unfolding of proteins in the presence of denaturant using fluorescence correlation spectroscopy, Biophysical Journal 88, 1413-1422.
  71. Chattopadhyay, K.,& Mazumdar, S. (2003) Stabilization of partially folded states of cytochrome c in aqueous micelles: effects of ionic and hydrophobic interactions, Biochemistry 42, 14606-14613.
  72. Chattopadhyay, K., Saffarian, S., Elson, E. L., & Frieden, C. (2002) Measurement of microsecond dynamic motion in the intestinal fatty acid binding protein by using fluorescence correlation spectroscopy, Proc. Natl. Acad. Sci. (USA) 99, 14171 – 14176.
  73. Frieden, C., Chattopadhyay, K., & Elson, E.L. (2002) What Fluorescence Correlation Spectroscopy can tell us about unfolded state of a protein. Adv. Prot. Chem. 62, 91-109.
  74. Chattopadhyay, K, Das, T. K, Majumdar, A, & Mazumdar, S (2002) NMR studies on interaction of lauryl maltoside with cytochrome c oxidase: a model for surfactant interaction with the membrane protein, J. Inor. Biochem 91, 116-124.
  75. Chattopadhyay, K., Zhong, S., Yeh, S. R., Rousseau, D., L., &Frieden, C. (2002) The Intestinal Fatty Acid Binding Protein: the role of turns in fast and slow folding processes, Biochemistry 41, 4040-4047.
  76. Chattopadhyay, K., & Mazumdar, S. (2001) Direct electrochemistry of heme proteins: effect of electrode surface modification by neutral surfactants, Bioelectrochemistry 53, 17-24.
  77. Chattopadhyay, K.& Mazumdar, S. (2000) Structural and conformational stability of horseradish peroxidase: effect of temperature and pH , Biochemistry 39, 263-270.
  78. Chattopadhyay, K.& Mazumdar, S. (1999) Direct electrochemical oxidation of horseradish peroxidase: cyclic voltammetric and spectroelectrochemical studies , New J Chem 23, 137-139. 
  79. Chattopadhyay, K.& Mazumdar, S. (1997) Direct electrochemistry of heme undecapeptide in aqueous surfactant solutions: The effect of hydrophobicity and axial ligation on redox potential of heme, CurrSci 73, 65-68.

*Corresponding author