Histidine-rich regions

Eu C, Maier RJ. Nucleotide sequences of two hydrogenase-related genes (hypA and hypB) from Bradyrhizobium japonicum, one of which (hypB) encodes an extremely histidine-rich region and guanine nucleotide-binding domains. Biochem Biophys Acta 1184 135-8. 

Excess copper is toxic to cells. On one hand, copper ions can avidly bind to biomolecules by ligand interaction with cysteines or by binding to histidine-rich regions. Copper ions could also be incorporated into proteins instead of zinc or other metal ions during biosynthesis. On the other hand, copper ions can form radicals by a Fenton-type reaction as shown in Eq. (1) ... 

The gene encodes a polypeptide of 647 amino acids, having eight transmembrane domains organized in two blocks of three and five. A histidine-rich region, which is considered... 

Three Ni-confaintng enzymes (see Nickel Enzymes Cofactors) appear to utilize Ni metallochaperones for enzyme activation. UreE appears to function in NP+ delivery to urease. The Klebsiella aerogenes protein binds 6 Ni per dimer, whereas that from Bacillus pasteurii binds a single Ni per dimer. The metal content differences arise from a His-Asp-His sequence near the middle and a histidine-rich region at the carboxyl terminus of the former protein. Truncated K aerogenes UreE protein, missing the His-rich... 

Favourable orientation of antibodies also appears possible on immobilized metal ions supports. Hale and Beidler [80] observed that an innate histidine-rich sequence located in the C-terminal portion of the Fc region, well-conserved in every antibody classes investigated from several species, binds strongly to the Co2+-IDA resin. Thus, antibodies bound on the supports are oriented with their combining site directed away from the resin and facilitate maximum antigen binding [81]. 

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