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X-ray crystal structures of three forms of human mitochondrial branched-chain aminotransferase (BCAT) were solved by molecular-replacement methods, using Escherichia coli BCAT as the search model. The enzyme is a homodimer and the polypeptide chain of each monomer has two domains. The small domain is composed of residues 1--175 and the large domain is(More)
The X-ray crystal structure of l-aspartate ammonia-lyase has been determined to 2.8 A resolution. The enzyme contains three domains, and each domain is composed almost completely of alpha helices. The central domain is composed of five long helices. In the tetramer, these five helices form a 20-helix cluster. Such clusters have also been seen in(More)
Comparisons between duplicated genes have shown that gene conversions play an important role in the evolution of multigene families. Previous comparisons have documented in the recently duplicated gamma-fetal globin genes of catarrhine primates, over 15 separate conversions affecting extensive stretches of coding and noncoding sequences. In the present(More)
The primary structure of the major arginine esteropeptidase from guinea pig prostate has been deduced from automated Edman degradation of peptides generated by clostripain, cyanogen bromide, endoproteinase Lys-C, and Staphylococcus aureus V8 protease digestion of the protein. The esteropeptidase is a single polypeptide chain comprised of 239 amino acids and(More)
2-(Aminoalkyl)-5-nitropyrazolo[3,4,5-kl]acridines were prepared from substituted anilines via the 1-chloro-4-nitroacridones followed by condensation with [(alkylamino)alkyl]hydrazines. Impressive activity was demonstrated for the 9-hydroxy, 9-alkoxy, and 9-acyloxy analogs in vitro on a L1210 leukemia line and in vivo against the P388 leukemia. Advanced(More)
The PvuII restriction-modification system is a type II system, which means that its restriction endonuclease and modification methyltransferase are independently active proteins. The PvuII system is carried on a plasmid, and its movement into a new host cell is expected to be followed initially by expression of the methyltransferase gene alone so that the(More)
Liver X receptors (LXRs) are nuclear receptors that regulate the metabolism of cholesterol and bile acids. Despite information on the specificity of their natural ligands, oxysterols, relatively little is known about the ligand binding site in LXRs. The helix 3 region in the ligand binding domain (LBD) of peroxisome proliferator-activated receptors (PPARs)(More)
Positional cloning has shown that the Huntington disease (HD) mutation is an expanded trinucleotide repeat in the IT15 gene. Although this mutation clearly produces the HD phenotype, the function of the Huntington disease protein remains undefined. One recent immunocytochemical study suggested that the IT15 protein preferentially localizes to the nucleus of(More)
Virtually all studies of the protein-folding reaction add either heat, acid, or a chemical denaturant to an aqueous protein solution in order to perturb the protein structure. When chemical denaturants are used, very high concentrations are usually necessary to observe any change in protein structure. In a solution with such high denaturant concentrations,(More)
Hormones and growth factors are generally released from larger precursors by limited proteolysis. The causative agents remain poorly defined with respect to location and properties. One subset of proteases, the glandular kallikreins, have been implicated in a few cases, in part because of their specific association with mature forms of some hormones.(More)