2mbr: Difference between revisions

[[Image:2mbr.jpg|left|200px]]<br /><applet load="2mbr" size="350" color="white" frame="true" align="right" spinBox="true"  

MurB catalyzes the second committed step in the synthesis of peptidoglycan, a key component of the bacterial cell wall. The crystal structures of both a S229A mutant and wild-type MurB in the presence of the substrate enolpyruvyl-UDP-N-acetylglucosamine were solved and refined at 1.8 A resolution. The single point mutation of residue 229 from serine to alanine eliminated a hydroxyl group which has previously been proposed to play a critical role as a proton donor during the second half-reaction of MurB, namely, reoxidation of FADH2 and reduction of the enolpyruvyl substrate. The mutation also resulted in the loss of the water molecule-hydrogen bonded to the serine hydroxyl in the wild-type structure changing the hydrogen-bonding network with in the active site. Comparison of the wild-type and S229A mutant structures confirms that the dramatic kinetic defect of an approximately 10(7)-fold decrease observed for the Ser 229 Ala mutant in the second half-reaction [Benson, T.E., Walsh, C.T., &amp; Massey, V. (1997) Biochemistry 36, 796-805] is a direct result of the loss of the serine hydroxyl moiety rather than other nonspecific active-site changes or general structural defects.

2MBR is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli] with <scene name='pdbligand=FAD:'>FAD</scene> and <scene name='pdbligand=EPU:'>EPU</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. This structure supersedes the now removed PDB entry 1MBR. Active as [http://en.wikipedia.org/wiki/UDP-N-acetylmuramate_dehydrogenase UDP-N-acetylmuramate dehydrogenase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.1.1.158 1.1.1.158] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2MBR OCA].  

[[Category: Benson, T E.]]

[[Category: Hogle, J M.]]

[[Category: Walsh, C T.]]

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