1nq4
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(New page: 200px<br /><applet load="1nq4" size="450" color="white" frame="true" align="right" spinBox="true" caption="1nq4" /> '''Solution Structure of Oxytetracycline Acyl C...)
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Revision as of 20:21, 20 November 2007
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Solution Structure of Oxytetracycline Acyl Carrier Protein
Overview
Type II polyketide synthases (PKSs) utilize a dedicated and essential acyl, carrier protein (ACP) in the biosynthesis of a specific polyketide, product. As part of our ongoing studies into the mechanisms and control of, polyketide biosynthesis, we report the second structure of a polyketide, synthase ACP. In this work, multidimensional, heteronuclear NMR was, employed to investigate the structure and dynamics of the ACP involved in, the biosynthesis of the commonly prescribed polyketide antibiotic, oxytetracycline (otc). An ensemble of 28 structures of the 95 amino acid, otc ACP (9916Da) was computed by simulated annealing with the inclusion of, 1132 experimental restraints. Atomic RMSDs about the mean structure for, all 28 models is 0.66 A for backbone atoms, 1.15 A for all heavy atoms, (both values calculated for the folded part of the protein (residues, 3-80)), and 0.41 A for backbone atoms within secondary structure. Otc ACP, adopts the typical right-handed, four-helix fold of currently known ACPs, but with the addition of a 13-residue flexible C-terminus. A comparison of, the global folds of all structurally characterized ACPs is described, illustrating that PKS ACPs show clear differences as well as similarities, to FAS ACPs. (15)N relaxation experiments for the protein backbone also, reveal that the long loop between helices I and II is flexible and helix, II, a proposed site of protein-protein interactions, shows conformational, exchange. The helices of the ACP form a rigid scaffold for the protein, but these are interspersed with an unusual proportion of flexible linker, regions.
About this Structure
1NQ4 is a Single protein structure of sequence from Streptomyces rimosus. Full crystallographic information is available from OCA.
Reference
Solution structure and dynamics of oxytetracycline polyketide synthase acyl carrier protein from Streptomyces rimosus., Findlow SC, Winsor C, Simpson TJ, Crosby J, Crump MP, Biochemistry. 2003 Jul 22;42(28):8423-33. PMID:12859187
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