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glmS of Thermus thermophilus HB8: an essential gene for cell‐wall synthesis identified immediately upstream of the S‐layer gene
Author(s) -
FernándezHerrero Luis Angel,
BadetDenisot MarieAnge,
Badet Bernard,
Berenguer José
Publication year - 1995
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.1365-2958.1995.mmi_17010001.x
Subject(s) - thermus thermophilus , biology , open reading frame , gene , genetics , microbiology and biotechnology , mutant , complementation , start codon , gene cluster , escherichia coli , nucleic acid sequence , structural gene , s layer , peptide sequence , messenger rna
A 30 kbp chromosomal region containing the S‐layer gene ( slpA ) from Thermus thermophilus HB8 was cloned from a λ phage gene library. DNA sequence analysis of the region upstream to the slpA gene revealed the presence of an open reading frame (ORF) which coded for a 604‐amino‐acid protein highly homologous to the glucosamine−6‐P synthases (EC 2.6.1.16) of both prokaryotic and eukaryotic origin. The identification of this ORF as the glucosamine−6‐P synthase gene from T. thermophilus ( glmS th ) has been carried out using three different strategies: (i) complementation of an Escherichia coli glmS mutant; (ii) in vivo insertional inactivation of the gene; and (iii) in vitro synthesis of glucosamine−6‐P at 60°C by a cytoplasmic extract of an overproducing E. coli strain. The glmS th gene is transcribed diver‐gently from slpA in a 2.0 kb mRNA which probably also includes a tryptophan tRNA gene ( trpT th ) identified at its 3′ extreme. As the products of both the glmS th and the slpA genes are main components of the cell envelope of T. thermophilus , their unusual clustering in the chromosome could be related to the existence of specific mechanisms for their co‐ordinate expression.