The lacY gene of Escherichia coli, which encodes the lac permease, has been modified by oligonucleotide-directed, site-specific mutagenesis such that each of the four histidine residues in the molecule is replaced with an arginine residue. Replacement of histidine-35 and histidine-39 with arginine has no apparent effect on permease activity. In contrast, replacement of either histidine-205 or h...

Lactobacillus buchneri ST2A vigorously decarboxylates histidine to the biogenic amine histamine, which is excreted into the medium. Cells grown in the presence of histidine generate both a transmembrane pH gradient, inside alkaline, and an electrical potential (delta psi), inside negative, upon addition of histidine. Studies of the mechanism of histidine uptake and histamine excretion in membra...

A cDNA encoding a rat liver glutathione S-transferase Ya subunit has been expressed in Escherichia coli and the expressed enzyme purified to homogeneity. In order to examine the catalytic role of histidine in the glutathione S-transferase Ya homodimer, site-directed mutagenesis was used to replace all three histidine residues (at positions 8, 143, and 159) by other amino acid residues. The repl...

It is more than 50 years since protein histidine phosphorylation was first discovered in 1962 by Boyer and co-workers; however, histidine kinases are still much less well recognized than the serine/threonine and tyrosine kinases. The best-known histidine kinases are the two-component signalling kinases that occur in bacteria, fungi and plants. The mechanisms and functions of these kinases, thei...

The requirement for dietary histidine was investigated in four normal and three chronically uremic men. Subjects lived in a metabolic unit where they were fed three isonitrogenous diets in the following order: a 40-g protein diet (28 plus or minus SD 8 days), a semi-synthetic amino acid diet deficient in histidine (35 plus or minus 2 days), and an amino acid diet which contained histidine (31 p...

Peptide histidine isoleucine, a 27 amino acid peptide with close amino acid sequence homology to vasoactive intestinal peptide and secretin, is distributed throughout the mammalian intestinal tract, where it has been localised to intramural neurones. An intestinal perfusion technique has been used to study the effect of intravenous peptide histidine isoleucine (44.5 pmol/kg/min) on water and el...

Experiments on the primary structure of a histidine-rich polypeptide isolated from the malarial parasite Plasmodium lophurae indicate that the smaller quantities of amino acids other than histidine form an integral part of the polypeptide and do not arise from a protein contaminating a histidine homopolymer. In culture, the parasites incorporate over 50% of exogenously supplied histidine into t...

Our goal was to explore the possible interactions of potential metallodrug (η5-Cp*)Rh(III) complexes with histidine containing biomolecules (peptides/proteins) in order understand most important thermodynamic factors influencing biospeciation and biotransformation complexes. To this end, here we report systematic solution structural study on interaction cation peptides their constituents ((N-me...

background: fragile histidine triad protein (fhit), as a known tumor suppressor protein, has been proposed to play crucial role in inhibiting p53 degradation by mdm2. studies have confirmed fhit interaction with p53 or mdm2, although functional interacting domains of fhit with mdm2 and/or p53 are not completely defined. thus, through determining the significant structural interacting domains of...

The aim of the present study was to investigate the cataract preventive effect of dietary histidine regimes in adult Atlantic salmon (Salmo salar L.) in seawater, both through manipulating the dietary histidine level and feeding period. Mean body weight of individually tagged Atlantic salmon at the start of the experiment was 1662 (sd 333) g. Low prevalence of mild cataracts were recorded in th...