1r0q
From Proteopedia
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'''Characterization of the conversion of the malformed, recombinant cytochrome rc552 to a 2-formyl-4-vinyl (Spirographis) heme''' | '''Characterization of the conversion of the malformed, recombinant cytochrome rc552 to a 2-formyl-4-vinyl (Spirographis) heme''' | ||
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[[Category: Todaro, T R.]] | [[Category: Todaro, T R.]] | ||
[[Category: Williams, P A.]] | [[Category: Williams, P A.]] | ||
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| - | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May 3 06:56:01 2008'' | |
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Revision as of 03:56, 3 May 2008
Characterization of the conversion of the malformed, recombinant cytochrome rc552 to a 2-formyl-4-vinyl (Spirographis) heme
Overview
Expression of the truncated (lacking an N-terminal signal sequence) structural gene of Thermus thermophilus cytochrome c(552) in the cytoplasm of Escherichia coli yields both dimeric (rC(557)) and monomeric (rC(552)) cytochrome c-like proteins [Keightley, J. A., et al. (1998) J. Biol. Chem. 273, 12006-12016], which form spontaneously without the involvement of cytochrome c maturation factors. Cytochrome rC(557) is comprised of a dimer and has been structurally characterized [McRee, D., et al. (2001) J. Biol. Chem. 276, 6537-6544]. Unexpectedly, the monomeric rC(552) transforms spontaneously to a cytochrome-like chromophore having, in its reduced state, the Q(oo) transition (alpha-band) at 572 nm (therefore called p572). The X-ray crystallographic structure of rC(552), at 1.41 A resolution, shows that the 2-vinyl group of heme ring I is converted to a [heme-CO-CH(2)-S-CH(2)-C(alpha)] conjugate with cysteine 11. Electron density maps obtained from isomorphous crystals of p572 at 1.61 A resolution reveal that the 2-vinyl group has been oxidized to a formyl group. This explains the lower energy of the Q(oo)() transition, the presence of a new, high-frequency band in the resonance Raman spectra at 1666 cm(-1) for oxidized and at 1646 cm(-1) for reduced samples, and the greatly altered, paramagnetically shifted (1)H NMR spectrum observed for this species. The overall process defines a novel mechanism for oxidation of the 2-vinyl group to a 2-formyl group and adds to the surprising array of chemical reactions that occur in the interaction of heme with the CXXCH sequence motif in apocytochromes c.
About this Structure
1R0Q is a Single protein structure of sequence from Thermus thermophilus. Full crystallographic information is available from OCA.
Reference
Cytochrome rC552, formed during expression of the truncated, Thermus thermophilus cytochrome c552 gene in the cytoplasm of Escherichia coli, reacts spontaneously to form protein-bound 2-formyl-4-vinyl (Spirographis) heme., Fee JA, Todaro TR, Luna E, Sanders D, Hunsicker-Wang LM, Patel KM, Bren KL, Gomez-Moran E, Hill MG, Ai J, Loehr TM, Oertling WA, Williams PA, Stout CD, McRee D, Pastuszyn A, Biochemistry. 2004 Sep 28;43(38):12162-76. PMID:15379555 Page seeded by OCA on Sat May 3 06:56:01 2008
Categories: Single protein | Thermus thermophilus | Ai, J. | Bren, K L. | Fee, J A. | Gomez-Moran, E. | Hill, M G. | Hunsicker-Wang, L M. | Loehr, T M. | Luna, E. | McRee, D. | Oertling, W A. | Pastuszyn, A. | Patel, K M. | Sanders, D. | Stout, C D. | Todaro, T R. | Williams, P A. | Malformed cytochrome c
