ISSN:
1617-4623
Keywords:
Tryptophan synthase
;
trpA
;
Subunit interaction
;
Plant
;
Complementation
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract The tryptophan synthaseα subunit catalyzes the conversion of indole-3-glycerolphosphate to indole, the penultimate reaction in the biosynthesis of the essential amino acid tryptophan. A cDNA encodingArabidopsis thaliana tryptophan synthaseα(TSA1) was isolated by complementation of anEscherichia coli ΔtrpA mutation and by polymerase chain reaction amplification from a cDNA library using degenerate primers. ATSA1 genomic clone was also isolated and 5 kb of the DNA sequence determined. A single sequence in the Arabidopsis genome with homology to theTSA1 cDNA was detected by high-stringency genomic Southern blot hybridization. In contrast under hybridization conditions of reduced stringency, one or two additional homologous sequences were observed. A 1.4 kb transcript was detected in wild-type RNA with theTSA1 cDNA as a probe. Several lines of evidence, including immunoaffinity chromatography, suggest that the activeA. thaliana tryptophan synthase enzyme consists of a heterosubunit complex, presumably analogous to the prokaryoticα 2 β 2 complex. Immunoblot analysis indicated that the plant α andβ subunits are present throughout development.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF02191705
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