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Porins form aqueous channels that aid the diffusion of small hydrophilic molecules across the outer membrane of Gram-negative bacteria. The crystal structures of matrix porin and phosphoporin both reveal trimers of identical subunits, each subunit consisting of a 16-stranded anti-parallel beta-barrel containing a pore. A long loop inside the barrel(More)
DOPA decarboxylase (DDC) is responsible for the synthesis of the key neurotransmitters dopamine and serotonin via decarboxylation of L-3,4-dihydroxyphenylalanine (L-DOPA) and L-5-hydroxytryptophan, respectively. DDC has been implicated in a number of clinic disorders, including Parkinson's disease and hypertension. Peripheral inhibitors of DDC are currently(More)
The 2.4 A crystal structure of the vitamin B6-dependent enzyme 1-aminocyclopropane-1-carboxylate (ACC) synthase is described. This enzyme catalyses the committed step in the biosynthesis of ethylene, a plant hormone that is responsible for the initiation of fruit ripening and for regulating many other developmental processes. ACC synthase has 15 % sequence(More)
BACKGROUND OmpF porin is a trimeric integral membrane protein responsible for the passive transport of small hydrophilic molecules, such as nutrients and waste products, across the outer membrane of Escherichia coli. Very few membrane proteins have been crystallized in three dimensions, yet this stable protein can be obtained in several crystal forms.(More)
Aspartate aminotransferase is a pyridoxal phosphate-dependent enzyme that catalyses the transamination reaction: L-aspartate + 2-oxoglutarate----oxaloacetate + L-glutamate. The enzyme shuttles between its pyridoxal and pyridoxamine forms in a double-displacement process. This paper proposes a mechanism of action that delineates the dynamic role of the(More)
The crystal structures of the stable, closed complexes of chicken mitochondrial aspartate aminotransferase with the natural substrates L-aspartate and L-glutamate have been solved and refined at 2.4- and 2.3-A resolution, respectively. In both cases, clear electron density at the substrate-coenzyme binding site unequivocally indicates the presence of a(More)
The last step in cysteine biosynthesis in enteric bacteria is catalyzed by the pyridoxal 5'-phosphate-dependent enzyme O-acetylserine sulfhydrylase. Here we report the crystal structure at 2.2 A resolution of the A-isozyme of O-acetylserine sulfhydrylase isolated from Salmonella typhimurium. O-acetylserine sulfhydrylase shares the same fold with tryptophan(More)
Crystal structures are known for three members of the bacterial neutral protease family: thermolysin from Bacillus thermoproteolyticus (TLN), the neutral protease from Bacillus cereus (NEU), and the elastase of Pseudomonas aeruginosa (PAE), both in free and ligand-bound forms. Each enzyme consists of an N-terminal and C-terminal domain with the active site(More)
A new crystal structure of O-acetylserine sulfhydrylase (OASS) has been solved with chloride bound at an allosteric site and sulfate bound at the active site. The bound anions result in a new "inhibited" conformation, that differs from the "open" native or "closed" external aldimine conformations. The allosteric site is located at the OASS dimer interface.(More)
Phosphoserine aminotransferase (PSAT; EC, a member of subgroup IV of the aminotransferases, catalyses the conversion of 3-phosphohydroxypyruvate to l-phosphoserine. The crystal structure of PSAT from Escherichia coli has been solved in space group P212121 using MIRAS phases in combination with density modification and was refined to an R-factor of(More)