title: [Cloning and sequence analysis of aspartokinase genes from Corynebacterium crenatum].
abstract: Aspartokinase genes (ask) from wild-type Corynebacterium crenatum AS1.542 and an AEC-resistant mutant Corynebacterium crenatum CD945 were cloned and sequenced. Analysis of ask sequence shows a exchange in a single base pair at position 1199 from T to C, leading to an amino acid change in the beta subunit of Aspartokinase. Leu80 in the wild-type is converted to Pro80 in the feedback-resistant enzyme. The substitution is located in ACT domain, a region regulated by concentration of lysine. The ORF sequence of ask from C. crenatum AS 1.542 shows homologies of 97.23%, 97.55% and 97.62% to those from C. glutamicum, C. flavum and B. lactofermentum. And the amino acid sequence deduced from ORF displays homologies of 99.76%, 99.52% and 99.76%, respectively. But there is much variation in the upstream sequence of C. crenatum AS 1.542 ask promoter compared to those from other Corynebacteria.
authors.affiliation: Center for Microbial Biotechnology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100080, China.
authors.forename: Yangjian
authors.initials: Y
authors.lastname: Liu
authors.forename: Yingzi
authors.initials: Y
authors.lastname: Zhang
authors.forename: Jiang
authors.initials: J
authors.lastname: Wang
authors.forename: Yu
authors.initials: Y
authors.lastname: Wang
authors.forename: Zhihua
authors.initials: Z
authors.lastname: Yu
authors.forename: Jiuyuan
authors.initials: J
authors.lastname: Ding
mesh_terms: D000595:Amino Acid Sequence; D001222:Aspartate Kinase / Q000235:genetics*; D001483:Base Sequence; D003001:Cloning, Molecular; D003352:Corynebacterium / Q000145:classification / Q000235:genetics*; D004269:DNA, Bacterial / Q000235:genetics; D005798:Genes, Bacterial; D008239:Lysine / Q000235:genetics; D008969:Molecular Sequence Data; D017354:Point Mutation; D011401:Promoter Regions, Genetic / Q000235:genetics; D017422:Sequence Analysis, DNA
chemical_list: D004269:DNA, Bacterial; D001222:Aspartate Kinase; D008239:Lysine