title: Unusual effects of crowders on heme retention in myoglobin.
abstract: Myoglobin (Mb) undergoes pronounced heme loss under denaturing conditions wherein the proximal histidine gets protonated. Our data show that macromolecular crowding agents (both synthetic and protein based) can appreciably influence the extent of heme retention in Mb. Interestingly, glucose and sucrose, the monomeric constituents of dextran and ficoll-based crowders were much more effective in preventing heme dissociation of Mb, albeit, at much higher concentrations. The protein crowders BSA and lysozyme show very interesting results with BSA bringing about the maximum heme retention amongst all the crowding agents used while lysozyme induced heme dissociation even in the native state of Mb. The stark difference that these protein crowders exhibit when interacting with the heme protein is a testament to the varied interaction potentials that a test protein might be exposed to in the physiological (crowded) milieu.
authors.affiliation: Department of Chemistry, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India.
authors.forename: Jayanta
authors.initials: J
authors.lastname: Kundu
authors.affiliation: Department of Chemistry, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India.
authors.forename: Uddipan
authors.initials: U
authors.lastname: Kar
authors.affiliation: Department of Chemistry, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India.
authors.forename: Saurabh
authors.initials: S
authors.lastname: Gautam
authors.affiliation: Department of Chemistry, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India.
authors.forename: Sandip
authors.initials: S
authors.lastname: Karmakar
authors.affiliation: Department of Chemistry, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India. Electronic address: pramitc@chemistry.iitd.ac.in.
authors.forename: Pramit K
authors.initials: PK
authors.lastname: Chowdhury
mesh_terms: D000818:Animals; D002417:Cattle; D003911:Dextrans / Q000494:pharmacology; D006418:Heme / Q000378:metabolism*; D009113:Muramidase / Q000494:pharmacology; D009211:Myoglobin / Q000737:chemistry / Q000378:metabolism*; D011092:Polyethylene Glycols / Q000494:pharmacology; D011485:Protein Binding / Q000187:drug effects; D011489:Protein Denaturation / Q000187:drug effects; D012710:Serum Albumin, Bovine / Q000494:pharmacology
chemical_list: D003911:Dextrans; D009211:Myoglobin; D012710:Serum Albumin, Bovine; D011092:Polyethylene Glycols; D006418:Heme; D009113:Muramidase
keywords: BSA; Excluded volume effect; Glucose and sucrose; Heme retention; Lysozyme; Macromolecular crowder; Soft interaction