Disease relevance of guaA

• The E. coli guaA gene encoding GMPS was cloned into a tac expression vector, overexpressed, and its gene product purified [1].
• Cloning and sequence of Bacillus subtilis purA and guaA, involved in the conversion of IMP to AMP and GMP [2].
• By connecting the PL promoter of lambda phage, the SD sequence of trpL of E. coli, and ATG, at a suitable position upstream of the guaA gene, we obtained plasmid pPLA66 [3].

High impact information on guaA

• A 68-base pair intercistronic region separates guaA from the upstream guaB gene in the polycistronic guaBA operon [4].
• The guaA gene was subcloned from the Clarke and Carbon (Clarke, L., and Carbon, J. (1976) Cell 9, 91-99) plasmid pLC34-10, and the nucleotide sequence was determined [4].
• GMP synthetase (EC 6.3.4.1), a glutamine amido-transferase encoded by the guaA gene, catalyzes the synthesis of GMP from XMP [4].
• Other strains carrying spontaneous mutations resulting in guanine or xanthine auxotrophy (guaA or guaB lesions, respectively) all allowed lambda Ots replication at 39 degrees C; Ots suppression in these strains was also abolished by addition of guanine to the medium [5].
• PCR-mediated deletion mutagenesis and cloning identified a 120-bp fragment upstream from the guaA gene to be the actual regulator [6].

Chemical compound and disease context of guaA

• Effects of xapA and guaA Disruption on Inosine Accumulation in Escherichia coli [7].
• To improve the efficiency of the enzymatic conversion of 5'-xanthylic acid (XMP) to 5'-guanylic acid (GMP), we attempted to increase the activity of the conversion enzyme, XMP aminase (GMP synthetase) encoded by the guaA gene in Escherichia coli [3].

Biological context of guaA

• Through contour-clamped homogeneous electric field electrophoresis, this cluster of clones was shown to reside on a 200-kb NotI fragment bridging SfiI fragments of 150 and 250 kb and was oriented with respect to the purA and guaA loci, developing an accurate physical map of the region surrounding the origin of replication [8].
• Primer extension analysis mapped the transcription start site to be the first 'G' residue of the translation start codon GTG of the guaA gene [6].

Analytical, diagnostic and therapeutic context of guaA

• The nucleotide sequences of purA and guaA were determined from a series of gene fragments isolated by polymerase chain reaction amplification, library screening, and plasmid rescue techniques [2].

References