Acyl group specificity at the active site of tetrahydridipicolinate N-succinyltransferase.

Tetrahydrodipicolinate N-succinyltransferase (DapD) catalyzes the succinyl-CoA-dependent acylation of L-2-amino-6-oxopimelate to 2-N-succinyl-6-oxopimelate as part of the succinylase branch of the meso-diaminopimelate/lysine biosynthetic pathway of bacteria, blue-green algae, and plants. This pathway provides meso-diaminopimelate as a building block for cell wall peptidoglycan in most bacteria, and is regarded as a target pathway for antibacterial agents. We have solved the X-ray crystal structures of DapD in ternary complexes with pimelate/succinyl-CoA and L-2-aminopimelate with the nonreactive cofactor analog, succinamide-CoA.

The conformational change and active site structure of tetrahydrodipicolinate N-succinyltransferase.

Tetrahydrodipicolinate (THDP) N-succinyltransferase catalyzes the conversion of tetrahydrodipicolinate and succinyl-CoA to L-2-(succinylamino)-6-oxopimelate and CoA. This reaction represents the committed step of the succinylase branch of the diaminopimelate/L-lysine biosynthetic pathway by which many bacteria synthesize meso-diaminopimelate, a component of peptidoglycan, and L-lysine from L-aspartate. The crystal structures of THDP succinyltransferase in complex with the substrate/cofactor pairs L-2-aminopimelate/coenzyme A and L-2-amino-6-oxopimelate/coenzyme A have been determined and refined to 2.

Structure of the hexapeptide xenobiotic acetyltransferase from Pseudomonas aeruginosa.

The crystal structure of the xenobiotic acetyltransferase from Pseudomonas aeruginosa PA103 (PaXAT) has been determined, as well as that of its complex with the substrate chloramphenicol and the cofactor analogue desulfo-coenzyme A. PaXAT is a member of the large hexapeptide acyltransferase family of enzymes that display tandem repeated copies of a six-residue hexapeptide repeat sequence motif encoding a left-handed parallel beta helix (L betaH) structural domain. The xenobiotic acetyltransferase class of hexapeptide acyltransferases is composed of microbial enzymes that utilize acetyl-CoA to acylate a variety of hydroxyl-bearing acceptors.

The role of proteolysis in the processing and assembly of 11S seed globulins.

11S seed storage proteins are synthesized as precursors that are cleaved post-translationally in storage vacuoles by an asparaginyl endopeptidase. To study the specificity of the reaction catalyzed by this asparaginyl endopeptidase, we prepared a series of octapeptides and mutant legumin B and G4 glycinin subunits. These contained amino acid mutations in the region surrounding the cleavage site.

Purification and crystallization of Pseudomonas aeruginosa chloramphenicol acetyltransferase.

A chloramphenicol acetyltransferase from Pseudomonas aeruginosa genomic DNA has been overexpressed, refolded, purified, and crystallized. Crystals suitable for a three-dimensional x-ray structure determination were obtained from solutions of polyethyleneglycol methyl ether 2000 containing NiCl2 at pH 8.5.