Disease relevance of hemB

• Plasmids containing DNA from the green photosynthetic bacterium Chlorobium vibrioforme complement a heme-requiring Escherichia coli hemB mutant that is deficient in porphobilinogen (PBG) synthase activity [1].
• Transposition of IS2 into the hemB gene of Escherichia coli K-12 [2].
• A site-directed Staphylococcus aureus hemB mutant is a small-colony variant which persists intracellularly [3].
• The results allowed us to identify an open reading frame whose nucleotide sequence presented a homology of 63% to the sequence of the hemB gene of Bacillus subtilis and of 55% to the sequence of the hemB gene of Escherichia coli K12 [4].

High impact information on hemB

• Between hemD and hemB there is an intervening open reading frame that is oriented in the opposite direction and encodes a protein with a predicted amino acid sequence significantly similar to that of inositol monophosphatase, an enzyme that is not involved in tetrapyrrole biosynthesis [1].
• We isolated a hemB mutant, due to homologous recombination, by growth at a nonpermissive temperature and selection for erythromycin resistance [3].
• The SCV phenotype of the hemB mutant was reversed by growth with hemin or by complementation with intact hemB [3].
• Therefore, we generated a stable mutant in electron transport by interrupting one of the hemin biosynthetic genes, hemB, in S. aureus by inserting an ermB cassette into hemB [3].
• This first report of IS2 insertion into hemB suggests that this gene may be a preferred target for insertion of this transposable element [2].

Chemical compound and disease context of hemB

• The Escherichia coli hemB gene, which encodes 5-aminolevulinic acid dehydratase, and was cloned into pTZ18U, a multicopy plasmid, was sequenced [5].

Biological context of hemB

• Sequencing of the hemB gene indicated the presence of an open reading frame (ORF) of 1051 nucleotides, which should correspond to the HemB protein [6].
• No other nucleotide sequences, except those belonging to known hemB genes, presented significant homologies to our sequence [4].
• To clone the hemB gene of Staphylococcus aureus we used Tn917-mediated transposon mutagenesis [4].

Associations of hemB with chemical compounds

• Then ALA is converted to Porphobilinogen (PBG) by the ALA dehydratase (hemB gene) [7].

Other interactions of hemB

• Strikingly, the malarial FC lacks a bipartite presequence at its N-terminus, unlike delta-aminolevulinic acid dehydratase of the same organism [8].

Analytical, diagnostic and therapeutic context of hemB

• PCR and Southern hybridization demonstrated that the mutation of the SCV of E. coli was localized in the hemB gene and was most likely due to a deletion of the hemB gene [9].
• Cloning and sequence analysis of the hemB gene of Staphylococcus aureus [4].

References