title: Crystallization of the FAD-independent acetolactate synthase of Klebsiella pneumoniae.
abstract: Leucine and valine are formed in a common pathway from pyruvate in which the first intermediate is 2-acetolactate. In some bacteria, this compound also has a catabolic fate as the starting point for the butanediol fermentation. The enzyme (EC 4.1.3.18) that forms 2-acetolactate is known as either acetohydroxyacid synthase (AHAS) or acetolactate synthase (ALS), with the latter name preferred for the catabolic enzyme. A significant difference between AHAS and ALS is that the former requires FAD for catalytic activity, although the reason for this requirement is not well understood. Both enzymes require the cofactor thiamine diphosphate. Here, the crystallization and preliminary X-ray diffraction analysis of the Klebsiella pneumoniae ALS is reported. Data to 2.6 A resolution have been collected at 100 K using a rotating-anode generator and an R-AXIS IV++ detector. Crystals have unit-cell parameters a = 137.4, b = 143.9, c = 134.4 A, alpha = 90, beta = 108.4, gamma = 90 degrees and belong to space group C2. Preliminary analysis indicates that there are four monomers located in each asymmetric unit.
authors.affiliation: Centre for Protein Structure, Function and Engineering, Department of Biochemistry and Molecular Biology, School of Molecular and Microbial Sciences. The University of Queensland, Brisbane QLD 4072, Australia.
authors.forename: S S
authors.initials: SS
authors.lastname: Pang
authors.forename: L W
authors.initials: LW
authors.lastname: Guddat
authors.forename: R G
authors.initials: RG
authors.lastname: Duggleby
mesh_terms: D000095:Acetolactate Synthase / Q000737:chemistry*; D018360:Crystallography, X-Ray / Q000379:methods*; D005182:Flavin-Adenine Dinucleotide / Q000737:chemistry*; D007711:Klebsiella pneumoniae / Q000201:enzymology*; D010957:Plasmids / Q000378:metabolism; D013696:Temperature
chemical_list: D005182:Flavin-Adenine Dinucleotide; D000095:Acetolactate Synthase