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Localisation of a strongly conserved section of coding sequence in glutamate dehydrogenase genes
Author(s) -
Mattaj Iain W.,
McPherson Michael J.,
Wootton John C.
Publication year - 1982
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(82)81003-x
Subject(s) - section (typography) , library science , sociology , computer science , operating system
NADP-specific glutamate dehydrogenase (NADP-GDH; EC 1.4.1.4) is a major enzyme of ammonium assimilation in many prokaryotic and eukaryotic microorganisms. Many enzymological and physiological studies have been made (review [1]) but little is known about the organisation and regulation of genes determining glutamate dehydrogenases (GDHs). The g&l gene of Escherichia coli K12, which encodes NADP-GDH, has been cloned in several laboratories (12-41 and this work) by selection of recombinant plasmids that complement a glutamate auxotroph of E. coli lacking both NADP-GDH and glutamate synthase. We have determined most of the DNA sequence of the E. coli gdhA gene, and report here a section of coding sequence that is very strongly conserved in prokaryotic and eukaryotic NADPGDHs. The mammalian GDHs, which can utilise either NADP or NAD (EC 1.4.1.3), and a fungal NAD-specific GDH (EC 1.4.1.2), possess corre‘spending sequences that are less strongly homologous. This sequence comparison suggests that genes encoding these 3 classes of GDHs, of different coenzyme specificity, diverged at a very early stage of evolution before the divergence of a separate eukaryotic line. We also report the map positions of the chromosomal g&Al point mutation and some restriction sites around the g&A region of E. coli.