Mycobacteria express enzymes from both the de novo and purine-salvage pathways. However, the regulation of these processes and the roles of individual metabolic enzymes have not been sufficiently detailed. Both Mycobacterium tuberculosis (Mtb) and Mycobacterium smegmatis (Msm) possess three guaB genes, but information is only available on guaB2, which encodes an essential inosine 5'-monophosphate dehydrogenase (IMPDH) involved in de novo purine biosynthesis. This study shows that guaB1, annotated in databases as a putative IMPDH, encodes a guanosine 5'-monophosphate reductase (GMPR), which recycles guanosine monophosphate to inosine monophosphate within the purine-salvage pathway and contains a cystathionine-β-synthase domain (CBS), which is essential for enzyme activity. GMPR activity is allosterically regulated by the ATP/GTP ratio in a pH-dependent manner. Bioinformatic analysis has indicated the presence of GMPRs containing CBS domains across the entire Actinobacteria phylum.

• Klíčová slova
• CBS domain, GMPR, Mycobacterium, guaB1, purine biosynthesis,
• MeSH
• adenosintrifosfát MeSH
• cystathionin-beta-synthasa genetika   MeSH
• cystathionin * MeSH
• GMP-reduktasa genetika   metabolismus   MeSH
• guanosintrifosfát MeSH
• IMP-dehydrogenasa genetika   metabolismus   MeSH
• inosin MeSH
• inosinmonofosfát metabolismus   MeSH
• kyselina 5'-guanylová metabolismus   MeSH
• Mycobacterium tuberculosis * metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• adenosintrifosfát MeSH
• cystathionin-beta-synthasa MeSH
• cystathionin * MeSH
• GMP-reduktasa MeSH
• guanosintrifosfát MeSH
• IMP-dehydrogenasa MeSH
• inosin MeSH
• inosinmonofosfát MeSH
• kyselina 5'-guanylová MeSH