Learn More
Organohalide-respiring microorganisms can use a variety of persistent pollutants, including trichloroethene (TCE), as terminal electron acceptors. The final two-electron transfer step in organohalide respiration is catalyzed by reductive dehalogenases. Here we report the x-ray crystal structure of PceA, an archetypal dehalogenase from Sulfurospirillum(More)
Biocatalysis continues to emerge as a powerful technique for the efficient synthesis of optically pure pharmaceuticals that are difficult to access via conventional chemistry. The power of biocatalysis can be enhanced if two or more reactions can be achieved by a single whole cell biocatalyst containing a pathway designed de-novo to facilitate a required(More)
Two-component systems (TCSs), which comprise sensor histidine kinases (SHK) and response-regulator proteins, represent the predominant strategy by which prokaryotes sense and respond to a changing environment. Despite paramount biological importance, a dearth exists of intact SHK structures containing both sensor and effector modules. Here, we report the(More)
Photosystem II (PSII) catalyzes a key step in photosynthesis, the oxidation of water to oxygen. Excellent structural models exist for the dimeric PSII core complex of cyanobacteria, but higher order physiological assemblies readily dissociate when solubilized from the native thylakoid membrane with detergent. Here, we describe the crystallization of PSII(More)
Aminotransferase enzymes catalyse the reversible substitution of a keto group for an amino group. While this reaction is highly stereoselective with respect to the amino group, each enzyme can usually catalyse the turnover of a number of different substrates. As the substrate range cannot be inferred from the sequence, it remains an early bottleneck when(More)
Adrenal medullary chromaffin cells maintained in vitro were prelabeled with [3H]inositol and the accumulation of [3H]inositol-1-phosphate, was determined following stimulation with a variety of pharmacological agents. Carbachol, bradykinin, and histamine produced significantly greater accumulation of [3H] inositol-1-phosphate over basal levels, with(More)
The three-dimensional structure of the Sulfolobus solfataricus serine:pyruvate aminotransferase has been determined to 1.8 Å resolution. The structure of the protein is a homodimer that adopts the type I fold of pyridoxal 5'-phosphate (PLP)-dependent aminotransferases. The structure revealed the PLP cofactor covalently bound in the active site to the(More)
Bovine adrenal medullary chromaffin cells, prelabeled with [3H]norepinephrine, released a large proportion of cellular 3H-labeled catecholamines (CAs) when stimulated with nicotine, K+, histamine, gamma-aminobutyric acid (GABA) and several peptidic hormones [bradykinin, angiotensin II, thyrotropin releasing hormone (TRH) and neurotensin]. The(More)
Histamine is a potent secretagogue for opioid pentapeptides (Met- and Leu-enkephalin) in adrenal chromaffin cells in vitro. This effect is dependent on extracellular Ca2+ and is reduced by Ca2+ channel blockers such as Co2+, D 600, and nifedipine. Moreover, histamine also produced a profound compensatory increase in cellular peptide content after 48 h of(More)
The TIP49a and TIP49b proteins belong to the family of AAA+ ATPases and play essential roles in vital processes such as transcription, DNA repair, snoRNP biogenesis, and chromatin remodeling. We report the crystal structure of a TIP49b hexamer and the comparative analysis of large-scale conformational flexibility of TIP49a, TIP49b, and TIP49a/TIP49b(More)