2png: Difference between revisions

The synthases that produce fatty acids in mammals (FASs) are arranged as large multidomain polypeptides. The growing fatty acid chain is bound covalently during chain elongation and reduction to the acyl carrier protein (ACP) domain that is then able to access each catalytic site. In this work we report the high-resolution nuclear magnetic resonance (NMR) solution structure of the isolated rat fatty acid synthase apoACP domain. The final ensemble of NMR structures and backbone (15)N relaxation studies show that apoACP adopts a single, well defined fold. On conversion to the holo form, several small chemical shift changes are observed on the ACP for residues surrounding the phosphopantetheine attachment site (as monitored by backbone (1)H-(15)N correlation experiments). However, there are negligible chemical shift changes when the holo form is modified to either the hexanoyl or palmitoyl forms. For further NMR analysis, a (13)C,(15)N-labeled hexanoyl-ACP sample was prepared and full chemical shift assignments completed. Analysis of two-dimensional F(2)-filtered and three-dimensional (13)C-edited nuclear Overhauser effect spectroscopy experiments revealed no detectable NOEs to the acyl chain. These experiments demonstrate that unlike other FAS ACPs studied, this Type I ACP does not sequester a covalently linked acyl moiety, although transient interactions cannot be ruled out. This is an important mechanistic difference between the ACPs from Type I and Type II FASs and may be significant for the modulation and regulation of these important mega-synthases.

2PNG is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Rattus_norvegicus Rattus norvegicus]. This structure supersedes the now removed PDB entry 1N8L. Active as [http://en.wikipedia.org/wiki/Fatty-acid_synthase Fatty-acid synthase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.3.1.85 2.3.1.85] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2PNG OCA].  

[[Category: Arthur, C J.]]

[[Category: Crump, M P.]]

[[Category: Evans, S E.]]

[[Category: Ploskon, E A.]]

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