Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.30.1 (S1 nuclease)
 3,660 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

IMP dehydrogenase, the product of the guaB locus in Escherichia coli K12, catalyzes the synthesis of XMP by the NAD+ dependent oxidation of IMP. The guaB locus has been subcloned from the Clarke and Carbon plasmid pLC34-10. The sequence of the guaB structural gene and surrounding DNA was determined by the dideoxy chain termination method of Sanger. The 1.533 kb guaB gene encodes an IMP dehydrogenase subunit of molecular weight 54,512. S1 nuclease mapping placed the site of guaBA mRNA initiation approximately 188 bp from the start of the guaB structural gene. The -10 and -35 regions that define the guaBA promoter were located upstream of the start of the guaBA transcription initiation site. The control region of approximately 188 bp does not show any obvious potential for secondary structure. A secondary lambda att site has been identified 42 bp distal to the guaB start codon.
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PMID:Nucleotide sequence of the guaB locus encoding IMP dehydrogenase of Escherichia coli K12. 286 Jun 37

GMP synthetase (EC 6.3.4.1), a glutamine amido-transferase encoded by the guaA gene, catalyzes the synthesis of GMP from XMP. 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. The structural gene encodes a protein of 525 amino acid residues having a calculated Mr of 58,604. The amino acid sequence of the NH2 terminus of GMP synthetase was determined and used to verify the translation start site determined from the DNA sequence. A 68-base pair intercistronic region separates guaA from the upstream guaB gene in the polycistronic guaBA operon. The 3' end of the guaA mRNA was determined by S1 nuclease mapping. The 3' end of guaA mRNA is 36-37 nucleotides downstream of the translation stop codon within a region of dyad symmetry that resembles a rho-independent transcription termination site.
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PMID:Nucleotide sequence of the guaA gene encoding GMP synthetase of Escherichia coli K12. 389 45