title: Sequence and stability of the goat cytochrome c.
abstract: We have determined the sequence of mitochondrial cytochrome c (cyt-c) from the goat heart, and it was found to have a unique amino acid sequence among all amino acid sequences of cyt-c reported till date. Its sequence alignment with the bovine cytochrome c (b-cyt-c) led us to conclude that the goat cytochrome c (g-cyt-c) differs in amino acid sequence from b-cyt-c at only one position, i.e., Pro44(bovine) --> Ala44(goat). It has been observed that guanidinium chloride (GdmCl) induces a two-state transition between the native (N) and denatured (D) states of g-cyt-c. This conclusion is reached from the coincidence of GdmCl-induced transition curves monitored by measurements of absorbance at 405, 530 and 695 nm and circular dichroism (CD) at 222, 416 and 405 nm. Analysis of denaturation curves for the Gibbs energy of stabilization suggests that the stability of g-cyt-c is, within experimental errors, identical to that of b-cyt-c. We have also measured the effect of temperature on the equilibrium, N state <--> D state of g-cyt-c in the presence of different GdmCl concentrations. These measurements gave values of transition temperature (T(m)), changes in enthalpy (DeltaH(m)) and heat capacity (DeltaC(p)) of g-cyt-c in the absence of GdmCl, which are compared with those of b-cyt-c. We have used crystal structure coordinates of b-cyt-c to predict the structure and stability of g-cyt-c, which are compared with those of the bovine protein.
authors.affiliation: Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, India.
authors.forename: Hamidur
authors.initials: H
authors.lastname: Rahaman
authors.forename: Khurshid Alam
authors.initials: KA
authors.lastname: Khan
authors.forename: Imtaiyaz
authors.initials: I
authors.lastname: Hassan
authors.forename: Mohd
authors.initials: M
authors.lastname: Wahid
authors.forename: S Baskar
authors.initials: SB
authors.lastname: Singh
authors.forename: Tej P
authors.initials: TP
authors.lastname: Singh
authors.forename: Ali Akbar
authors.initials: AA
authors.lastname: Moosavi-Movahedi
authors.forename: Faizan
authors.initials: F
authors.lastname: Ahmad
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002417:Cattle; D002942:Circular Dichroism; D045304:Cytochromes c / Q000737:chemistry* / Q000302:isolation & purification; D006041:Goats; D019791:Guanidine / Q000737:chemistry / Q000494:pharmacology*; D006358:Hot Temperature; D008954:Models, Biological; D008969:Molecular Sequence Data; D011489:Protein Denaturation / Q000187:drug effects; D017510:Protein Folding; D017434:Protein Structure, Tertiary; D013696:Temperature; D013816:Thermodynamics
chemical_list: D045304:Cytochromes c; D019791:Guanidine