1or5
From Proteopedia
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SOLUTION STRUCTURE OF THE HOLO-FORM OF THE FRENOLICIN ACYL CARRIER PROTEIN, MINIMIZED MEAN STRUCTURE
Overview
During polyketide biosynthesis, acyl carrier proteins (ACPs) perform the, central role of transferring polyketide intermediates between active sites, of polyketide synthase. The 4'-phosphopantetheine prosthetic group of a, holo-ACP is a long and flexible arm that can reach into different active, sites and provide a terminal sulfhydryl group for the attachment of acyl, groups through a thioester linkage. We have determined the solution, structure and characterized backbone dynamics of the holo form of the, frenolicin acyl carrier protein (fren holo-ACP) by nuclear magnetic, resonance (NMR). Unambiguous assignments were made for 433 hydrogen atoms, 333 carbon atoms, and 84 nitrogen atoms, representing a total of 94.6% of, the assignable atoms in this protein. From 879 meaningful NOEs and 45, angle constraints, a family of 24 structures has been calculated. The, solution structure is composed of three major alpha-helices packed in a, bundle with three additional short helices in intervening loops; one of, the short helices slowly exchanges between two conformations., Superposition of the major helical regions on the mean structure yields, average atomic rmsd values of 0.49 +/- 0.09 and 0.91 +/- 0.08 A for, backbone and non-hydrogen atoms, respectively. Although the three-helix, bundle fold is conserved among acyl carrier proteins involved in fatty, acid synthases and polyketide synthases, a detailed comparison revealed, that ACPs from polyketide biosynthetic pathways are more related to each, other in tertiary fold than to their homologues from fatty acid, biosynthetic pathways. Comparison of the free form of ACPs (NMR structures, of fren ACP and the Bacillus subtilis ACP) with the substrate-bound form, of ACP (crystal structure of butyryl-ACP from Escherichia coli) suggests, that conformational exchange plays a role in substrate binding.
About this Structure
1OR5 is a Single protein structure of sequence from Streptomyces fradiae. Full crystallographic information is available from OCA.
Reference
Solution structure and backbone dynamics of the holo form of the frenolicin acyl carrier protein., Li Q, Khosla C, Puglisi JD, Liu CW, Biochemistry. 2003 Apr 29;42(16):4648-57. PMID:12705828
Page seeded by OCA on Sun Nov 25 01:18:15 2007
Categories: Single protein | Streptomyces fradiae | Khosla, C. | Li, Q. | Liu, C.W. | Puglisi, J. | Acp | Acyl carrier protein | Biosynthesis | Frenolicin | Holo | Pks | Polyketide synthase
