Aspartate carbamoyltransferase from a psychrophilic deep-sea bacterium, Vibrio strain 2693: properties of the enzyme, genetic organization and synthesis in Escherichia coli.
The aspartate carbamoyltransferase (ATCase) genes of psychrophilic Vibrio strain 2693 were cloned by complementation in Escherichia coli and the enzyme was partly characterized. The genes constitute a pyrBI operon homologous to the cognate structure in E. coli where pyrB and pyrI respectively encode the catalytic and the regulatory chains of ATCase. The strong sequence similarities noted between Vibrio and E. coli ATCases include extensive conservation of residues involved in interactions between subunits, suggesting that the two enzymes have very similar tertiary and quaternary structures. Vibrio ATCase is, however, not activated by ATP and not synergistically inhibited by CTP and UTP. It is also much more thermolabile than E. coli ATCase. With respect to Pyrococcus abyssi and E. coli ATCases, Vibrio ATCase presents marked differences in composition which could be related to its psychrophilic character. The results of these structural and functional comparisons indicate that Vibrio 2693 ATCase is a suitable model for biochemical studies on structure-function relationships in a 'cold' allosteric enzyme. The operon is expressed from a promoter which is immediately followed by a pyrimidine-rich leader ORF terminating within a putative transcription attenuator. These genetic and enzymic data strengthen the evolutionary relationship already noted between Vibrionaceae and Enterobacteriaceae.
Xu
Ying
Y
Microbiologie, Vrije Universiteit BrusselB-1070 Brussels, Belgium.|Flanders Interuniversity Institute for BiotechnologyB-1070 Brussels, Belgium.
Zhang
Yuanfu
Y
Epidemiology Institute, Beijing, The Peoples Republic of China.
Liang
Ziyuan
Z
Microbiologie, Vrije Universiteit BrusselB-1070 Brussels, Belgium.
Van de Casteele
Mark
M
Flanders Interuniversity Institute for BiotechnologyB-1070 Brussels, Belgium.|Microbiologie, Vrije Universiteit BrusselB-1070 Brussels, Belgium.
Legrain
Christianne
C
Research Institute CERIA-COOVI Emile Grysonlaan1, B-1070 Brussels, Belgium.
Glansdorff
Nicolas
N
Microbiologie, Vrije Universiteit BrusselB-1070 Brussels, Belgium.|Research Institute CERIA-COOVI Emile Grysonlaan1, B-1070 Brussels, Belgium.|Flanders Interuniversity Institute for BiotechnologyB-1070 Brussels, Belgium.
D000595:Amino Acid Sequence; D001221:Aspartate Carbamoyltransferase / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D003001:Cloning, Molecular; D003080:Cold Temperature; D004269:DNA, Bacterial; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics; D005798:Genes, Bacterial; D008969:Molecular Sequence Data; D009876:Operon; D011401:Promoter Regions, Genetic; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D013329:Structure-Activity Relationship; D013696:Temperature; D014158:Transcription, Genetic; D014169:Transformation, Bacterial; D014733:Vibrio / Q000737:chemistry / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development
D004269:DNA, Bacterial; D001221:Aspartate Carbamoyltransferase