2a5h: Difference between revisions

[[Image:2a5h.gif|left|200px]]<br /><applet load="2a5h" size="350" color="white" frame="true" align="right" spinBox="true"  

The x-ray crystal structure of the pyridoxal-5'-phosphate (PLP), S-adenosyl-L-methionine (SAM), and [4Fe-4S]-dependent lysine-2,3-aminomutase (LAM) of Clostridium subterminale has been solved to 2.1-A resolution by single-wavelength anomalous dispersion methods on a L-selenomethionine-substituted complex of LAM with [4Fe-4S]2+, PLP, SAM, and L-alpha-lysine, a very close analog of the active Michaelis complex. The unit cell contains a dimer of hydrogen-bonded, domain-swapped dimers, the subunits of which adopt a fold that contains all three cofactors in a central channel defined by six beta/alpha structural units. Zinc coordination links the domain-swapped dimers. In each subunit, the solvent face of the channel is occluded by an N-terminal helical domain, with the opposite end of the channel packed against the domain-swapped subunit. Hydrogen-bonded ionic contacts hold the external aldimine of PLP and L-alpha-lysine in position for abstraction of the 3-pro-R hydrogen of lysine by C5' of SAM. The structure of the SAM/[4Fe-4S] complex confirms and extends conclusions from spectroscopic studies of LAM and shows selenium in Se-adenosyl-L-selenomethionine poised to ligate the unique iron in the [4Fe-4S] cluster upon electron transfer and radical formation. The chain fold in the central domain is in part analogous to other radical-SAM enzymes.

2A5H is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Clostridium_subterminale Clostridium subterminale] with <scene name='pdbligand=ZN:'>ZN</scene>, <scene name='pdbligand=SO4:'>SO4</scene>, <scene name='pdbligand=SAM:'>SAM</scene>, <scene name='pdbligand=LYS:'>LYS</scene> and <scene name='pdbligand=SF4:'>SF4</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Lysine_2,3-aminomutase Lysine 2,3-aminomutase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=5.4.3.2 5.4.3.2] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2A5H OCA].  

[[Category: Frey, P A.]]

[[Category: Lepore, B W.]]

[[Category: Ruzicka, F J.]]

''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 16:23:47 2008''