THE MONOMERIC GLUTAMYL-TRANSFER RNA-SYNTHETASE FROM BACILLUS-SUBTILIS-168 AND ITS REGULATORY FACTOR - THEIR PURIFICATION, CHARACTERIZATION, AND THE STUDY OF THEIR INTERACTION

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  • 1 January 1983
    • journal article
    • research article
    • Vol. 258  (2) , 753-759
Abstract
The glutamyl-tRNA synthetase from B. subtilis was purified to homogeneity. It is a monomer of MW = 65,500 whose NH2-terminal sequence is Met-Asn-Glu-Val-Arg-Val-Arg-Tyr-Ser-Pro-Ser-Pro-Thr-Gly-His-Leu. The number of tryptic peptides indicates the absence of a significant amount of sequence duplication. Under certain conditions, this monomeric enzyme is co-purified with a polypeptide .beta. of MW = 46,000, which increases the affinity of the enzyme about 10-fold for glutamate and for ATP and stabilizes it against heat inactivation. .gamma.-Globulins prepared against the monomeric enzyme completely inhibit the glutamyl-tRNA synthetase activity of a B. subtilis extract and precipitate from this extract both the monomeric enzyme and the regulatory factor .beta.. These anti-.alpha. Ig do not precipitate pure .beta.. Thus, the glutamyl-tRNA synthetase of B. subtilis has a structure similar to that of the Escherichia coli enzyme and the .beta. factor functions, in the regulation of glutamyl-tRNA biosynthesis in vivo.