1hyh: Difference between revisions

[[Image:1hyh.jpg|left|200px]]<br /><applet load="1hyh" size="350" color="white" frame="true" align="right" spinBox="true"  

L-2-Hydroxyisocaproate dehydrogenase (L-HicDH) from Lactobacillus confusus, a homotetramer with a molecular mass of 33 kDa per subunit, belongs to the protein family of the NAD(+)-dependent L-2-hydroxycarboxylate dehydrogenases. L-HicDH was crystallized with ammonium sulphate as precipitant in the presence of NAD+. The crystals belong to the trigonal space group P3(2)21, with a = 135.9 A and c = 205.9 A, and diffract X-rays to 2.2 A resolution. The crystal structure was solved by Patterson search and molecular replacement techniques and refined to an R-value of 21.4% (2.2 to 8 A). The final structure model contains one NAD+ molecule and one sulphate ion per subunit, with 309 water molecules. An unusual feature of this crystal structure is the deviation of the protein subunits from non-crystallographic symmetry, which is so strong that it can be detected globally by self-rotation calculations in reciprocal space. This asymmetry is especially pronounced in the environment of the active site; it is reflected also in the nicotinamide conformation of NAD+ and allows some conclusions to be drawn about the catalytic mechanism. In this context, an "inner active site loop" is identified as a structural element of fundamental functional importance. Furthermore, with knowledge of the crystal structure of L-HicDH the differences in substrate specificity between L-HicDH and the L-lactate dehydrogenases can be partly explained.

1HYH is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Weissella_confusa Weissella confusa] with <scene name='pdbligand=SO4:'>SO4</scene> and <scene name='pdbligand=NAD:'>NAD</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/L-lactate_dehydrogenase L-lactate dehydrogenase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.1.1.27 1.1.1.27] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1HYH OCA].  

[[Category: Hecht, H J.]]

''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 13:06:11 2008''