Premium
Molecular genetic analysis of the moa operon of Escherichia coli K‐12 required for molybdenum cofactor biosynthesis
Author(s) -
Rivers S. L.,
McNairn E.,
Blasco F.,
Giordano G.,
Boxer D. H.
Publication year - 1993
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.1993.tb01652.x
Subject(s) - biology , operon , orfs , mutant , genetics , molybdenum cofactor , locus (genetics) , gene , microbiology and biotechnology , escherichia coli , open reading frame , peptide sequence
Summary A 3.2 kb chromosomal DNA fragment which complements the defects in a series of twelve moa ::Mucts insertion mutants has been sequenced. Five open reading frames (ORFs) were identified and these are arranged in a manner consistent with their forming an operon. The encoded proteins (MoaA‐MoaE) have predicted molecular weights of 37346, 18665, 17234, 8843 and 16981 respectively. Examination of subclones of the whole locus in an expression system demonstrated the predicted products. N ‐terminal amino acid sequences for the moa A, B, C and E products confirmed the translational starts. Genetic analysis distinguished four classes of moa mutants corresponding to genes moaA, C, D and E. Potential promoter sequences upstream of moaA and a possible transcription termination signal have been identified. Genetic analysis of the chlA1 and chlM mutants, which have been biochemically characterized as defective in molybdopterin biosynthesis, indicates that these carry lesions in moaA and moaD respectively. The moa locus is orientated clockwise at 17.7 minutes in the chromosome.