Disease relevance of mobA

• The crystal structure of the Escherichia coli MobA protein provides insight into molybdopterin guanine dinucleotide biosynthesis [1].
• The structure of MobA has striking similarity to Bacillus subtilis SpsA, a nucleotide-diphospho-sugar transferase involved in sporulation [1].
• The product of the mobilization gene mob421 (42.2 kDa) is a member of the Bacteroides mobilization protein family, which includes the MobA of pBI143, NBUs, and Tn4555 [2].
• The requirement of MobA for molybdoenzymes with different molybdenum cofactors was analyzed in Rhodobacter capsulatus [3].

High impact information on mobA

• We report the first description of protein interactions between molybdenum cofactor biosynthetic proteins (MogA, MoeA, MobA, and MobB) and the aponitrate reductase (NarG) using a bacterial two-hybrid approach [4].
• We propose therefore that MobB is an adapter protein that acts in concert with MobA to achieve the efficient biosynthesis and utilization of molybdopterin guanine dinucleotide [5].
• Our results suggest an essential role for glycine 15 of MobA, either for GTP binding and/or catalysis, and an involvement of glycine 82 in the stabilization of the product-bound form of the enzyme [6].
• In Escherichia coli, the MobA protein links a guanosine 5'-phosphate to MPT forming molybdopterin guanine dinucleotide [1].
• MobA protein, encoded by the broad host-range plasmid R1162, is required for conjugal mobilization of this plasmid [7].

Chemical compound and disease context of mobA

• RESULTS: The crystal structure of the 21.6 kDa E. coli MobA has been determined by MAD phasing with selenomethionine-substituted protein and subsequently refined at 1 [8].

Biological context of mobA

• Gene walking analysis of the upstream region of mobA revealed an open reading frame (mobR) that encodes a transcriptional regulator of the MarR family [9].
• A primer extension experiment was performed to determine the transcription start site for mobA and identified it at 83 bp upstream of the mobA start codon, accompanied by a typical sigma(70)-type promoter [9].
• The operator site is located between the start codon and the promoter region for mobA, suggesting that MobR functions as a transcriptional repressor for mobA expression [9].
• pC221, a small nonconjugative staphylococcal plasmid, can be mobilized between staphylococci by pG01, a larger conjugative plasmid. pC221 carries the two transacting genes, mobA and mobB, which are needed for its mobilization [10].
• In this strain, 3-hydroxybenzoate hydroxylase (MobA) acts on the initial step of the degradation to produce 3,4-dihydroxybenzoate, which is subsequently subjected to the meta-cleavage pathway leading to tricarboxylic acid cycle intermediates [9].

Anatomical context of mobA

• Additional ORFs were shown to encode hypothetical proteins presumably required for holoenzyme assembly, interaction with the cell membrane, and transcriptional regulation, including a MobA homologue predicted to be specific for the synthesis of the molybdopterin cytidine dinucleotide cofactor [11].

Associations of mobA with chemical compounds

• Here, we report that MobR negatively regulates the expression of mobA, and that the repression is relieved by binding of 3-hydroxybenzoate, the substrate for MobA [9].
• This work also represents the first time that the MobA-mediated conversion of molybdopterin to molybdopterin guanine dinucleotide has been demonstrated directly without using the activation of a molybdoenzyme as an indicator for cofactor formation [12].
• MobA is essential for DMSO reductase and nitrate reductase activity, both enzymes containing the molybdopterin guanine dinucleotide cofactor (MGD), but not for active xanthine dehydrogenase, harboring the molybdopterin cofactor [3].

Other interactions of mobA

• The products of these genes create a site-specific single-stranded nick (mobA) and then facilitate DNA transfer (mobB) [10].

Analytical, diagnostic and therapeutic context of mobA

• Termination involves ligation of the transferred single strand by the plasmid-encoded MobA protein [13].

References