期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1990
卷号：87
期号：7
页码：2740-2744
DOI：10.1073/pnas.87.7.2740
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Escherichia coli encodes an enzyme, deoxyguanosine triphosphate triphosphohydrolase (dGTPase, EC 3.1.5.1 ), that cleaves dGTP into deoxyguanosine and tripolyphosphate. An E. coli mutant, optA1, contains a 50-fold increased level of dGTPase and cannot support the growth of phage T7 defective in [corrected] gene 1.2, whose product is an inhibitor of dGTPase. The optA1 mutation maps to 3.6 min on the E. coli chromosome and is closely linked to dapD. We have isolated the gene encoding dGTPase (dgt) from wild-type E. coli and determined its nucleotide sequence. The dgt gene lies immediately upstream of htrA and 6 kilobases from dapD, in the same region as the optA1 mutation. The dgt structural gene is 1515 base pairs, encoding a protein of 59,315 daltons, in agreement with the size and N-terminal amino acid sequence of the purified protein. An E. coli strain containing a null allele has no detectable phenotype when grown at 30-42 degrees C in rich medium. A transition of C to T in a potential promoter of dgt is required for expression of the optA1 phenotype.
