1hyh
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(New page: 200px<br /><applet load="1hyh" size="450" color="white" frame="true" align="right" spinBox="true" caption="1hyh, resolution 2.2Å" /> '''CRYSTAL STRUCTURE OF ...)
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Revision as of 14:47, 20 November 2007
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CRYSTAL STRUCTURE OF L-2-HYDROXYISOCAPROATE DEHYDROGENASE FROM LACTOBACILLUS CONFUSUS AT 2.2 ANGSTROMS RESOLUTION-AN EXAMPLE OF STRONG ASYMMETRY BETWEEN SUBUNITS
Overview
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.
About this Structure
1HYH is a Single protein structure of sequence from Weissella confusa with SO4 and NAD as ligands. Active as L-lactate dehydrogenase, with EC number 1.1.1.27 Full crystallographic information is available from OCA.
Reference
Crystal structure of L-2-hydroxyisocaproate dehydrogenase from Lactobacillus confusus at 2.2 A resolution. An example of strong asymmetry between subunits., Niefind K, Hecht HJ, Schomburg D, J Mol Biol. 1995 Aug 11;251(2):256-81. PMID:7643402
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