TY - JOUR
T1 - ArsAB, a novel enzyme from Sporomusa ovata activates phenolic bases for adenosylcobamide biosynthesis
AU - Chan, Chi Ho
AU - Escalante-Semerena, Jorge C.
PY - 2011/8
Y1 - 2011/8
N2 - In the homoacetogenic bacterium Sporomusa ovata, phenol and p-cresol are converted into α-ribotides, which are incorporated into biologically active cobamides (Cbas) whose lower ligand bases do not form axial co-ordination bonds with the cobalt ion of the corrin ring. Here we report the identity of two S.ovata genes that encode an enzyme that transfers the phosphoribosyl group of nicotinate mononucleotide (NaMN) to phenol or p-cresol, yielding α-O-glycosidic ribotides. The alluded genes were named arsA and arsB (for alpha-ribotide synthesis), arsA and arsB were isolated from a genomic DNA library of S.ovata. A positive selection strategy using an Escherichia coli strain devoid of NaMN:5,6-dimethylbenzimidazole (DMB) phosphoribosyltransferase (CobT) activity was used to isolate a fragment of S.ovata DNA that contained arsA and arsB, whose nucleotide sequences overlapped by 8bp. SoArsAB was isolated to homogeneity, shown to be functional as a heterodimer, and to have highest activity at pH9. SoArsAB also activated DMB to its α-N-glycosidic ribotide. Previously characterized CobT-like enzymes activate DMB but do not activate phenolics. NMR spectroscopy was used to confirm the incorporation of phenol into the cobamide, and mass spectrometry was used to identify SoArsAB reaction products.
AB - In the homoacetogenic bacterium Sporomusa ovata, phenol and p-cresol are converted into α-ribotides, which are incorporated into biologically active cobamides (Cbas) whose lower ligand bases do not form axial co-ordination bonds with the cobalt ion of the corrin ring. Here we report the identity of two S.ovata genes that encode an enzyme that transfers the phosphoribosyl group of nicotinate mononucleotide (NaMN) to phenol or p-cresol, yielding α-O-glycosidic ribotides. The alluded genes were named arsA and arsB (for alpha-ribotide synthesis), arsA and arsB were isolated from a genomic DNA library of S.ovata. A positive selection strategy using an Escherichia coli strain devoid of NaMN:5,6-dimethylbenzimidazole (DMB) phosphoribosyltransferase (CobT) activity was used to isolate a fragment of S.ovata DNA that contained arsA and arsB, whose nucleotide sequences overlapped by 8bp. SoArsAB was isolated to homogeneity, shown to be functional as a heterodimer, and to have highest activity at pH9. SoArsAB also activated DMB to its α-N-glycosidic ribotide. Previously characterized CobT-like enzymes activate DMB but do not activate phenolics. NMR spectroscopy was used to confirm the incorporation of phenol into the cobamide, and mass spectrometry was used to identify SoArsAB reaction products.
UR - http://www.scopus.com/inward/record.url?scp=80051576390&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=80051576390&partnerID=8YFLogxK
U2 - 10.1111/j.1365-2958.2011.07741.x
DO - 10.1111/j.1365-2958.2011.07741.x
M3 - Article
C2 - 21696461
AN - SCOPUS:80051576390
SN - 0950-382X
VL - 81
SP - 952
EP - 967
JO - Molecular Microbiology
JF - Molecular Microbiology
IS - 4
ER -