文章基本信息

标题：Primary structure of a key enzyme in plant tetrapyrrole synthesis: glutamate 1-semialdehyde aminotransferase.
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作者：B Grimm
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：11
页码：4169-4173
DOI：10.1073/pnas.87.11.4169
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：The formation of delta-aminolevulinate from glutamate 1-semialdehyde (GSA) is catalyzed by glutamate 1-semialdehyde aminotransferase (EC 5.4.3.8 ). The active form of the barley enzyme appears to be a dimer of identical subunits with a molecular mass of 46 kDa. From the purified enzyme, amino acid sequences of the N-terminal ends of the mature protein as well as an internal peptide were determined. DNA primers deduced from these peptide sequences were used to amplify with the polymerase chain reaction a cDNA sequence encoding part of the enzyme. Screening a cDNA library with this DNA fragment identified a full-length clone encoding the 49,540-Da precursor of the GSA aminotransferase. The transit peptide for chloroplast import consists of 34 amino acids. GSA aminotransferase and a precursor form were expressed on a multicopy plasmid in Escherichia coli. Both recombinant gene products reacted with an antibody against the barley GSA aminotransferase. Active barley GSA aminotransferase expressed in E. coli was shown to be active in assays of bacterial cell extracts. As a gene symbol for barley GSA aminotransferase, Gsa is proposed.