In the course of the studies presented in the preceding paper it was observed that Aerobacter aerogenes could grow on histidine as the sole source of carbon and nitrogen (1). The nature of the microbial enzymes responsible for the complete degradation of histidine was not known and appeared therefore to be an appropriate subject for investigation. After initiation of these studies, the results ...

The major determinant for the identity of alanine tRNAs is a single base pair in the acceptor helix that is proximal to the site of amino acid attachment. A 7-base-pair microhelix that recreates the acceptor helix can be charged with alanine. No other examples of charging of small helices with specific amino acids have been reported, to our knowledge. We show here that a 13-base-pair and an 8-b...

L-Histidinol has been found to be a potent, reversible inhibitor of protein synthesis in cultured human cells. When the culture medium contains 0.005 fll~ histidine, protein synthesis is inhibited 50% by 0.1 mM histidinol. Histidinol does not significantly affect the transport of histidine into cells or the amount of histidine accumulated in the free amino acid pool. Histidinol probably inhibit...

is identical with that found in the region of the active center of bovine trypsin, which includes histidine-29 and histidine-46, except that a serine residue (asterisk) replaces a tyrosine residue in the bovine enzyme. The sequence of one of the two other histidine-containing peptides bears some similarity to the sequence surrounding histidine-79 of bovine trypsin. The lack of structural homolo...

The his1 gene in Saccharomyces cerevisiae codes for phosphoribosyl transferase, an allosteric enzyme that catalyzes the initial step in histidine biosynthesis. Mutants that specifically alter the feedback regulatory function were isolated by selecting his1 prototrophic revertants that overproduce and excrete histidine. The prototrophs were obtained from diploids homoallelic for his1--7 and hete...

During the fusion of the influenza virus to the host cell, bending of the HA2 chain of hemagglutinin into a hairpin-shaped structure in a pH-dependent manner facilitates the fusion of the viral envelope and the endosomal membrane. To characterize the structural and dynamical responses of the hinge region of HA2 to pH changes and examine the role of a conserved histidine in this region (the hing...

Alkylation of ribonuclease A by iodoacetamide at pH 5.5 yields two products: inactive 3-carboxamidomethylhistidine12.ribonuclease and fully active S-carboxamidomethylmethionine ribonuclease. No derivative substituted at histidine-119 was detected. This is in marked contrast to the products obtained on alkylation by iodoacetate at pH 5.5. The rate of alkylation of histidine in ribonuclease by io...

Carbon supported Ni and NiCo catalysts are prepared for amino compounds electrooxidation. Their electrocatalytic behaviors toward 8 kinds of acids (glycine, alanine, histidine, methionine, proline, serine, tyrosine, cysteine) are...

A regulatory relationship in Bacillus subtilis between histidine and the synthesis of tryptophan exemplifies “metabolic interlock,” a phenomenon of regulatory interactions exerted between biochemical pathways. The enzymatic basis for the histidine-tryptophan relationship was examined. Histidine activates anthranilate synthetase by increasing the apparent value of VmSx. Hence, histidine antagoni...