Crystal Structure of Thymidylate Synthase from T4 Phage: Component of a Deoxynucleoside Triphosphate-Synthesizing Complex

Janet S. Finer-Moore, Gladys F. Maley, Frank Maley, William R. Montfort, Robert M. Stroud

Research output: Contribution to journalArticle

32 Scopus citations

Abstract

Thymidylate synthase from phage T4 (T4TS) is part of a complex of several enzymes required for coordinate DNA synthesis in infected Escherichia coli cells. It has been proposed that similar complexes of enzymes related to DNA synthesis are also functional in eukaryotes [Pardee, A. B. (1989) Science 246, 603–608]. To delineate the role of structure in the function of this complex, we have solved the structure of T4TS as a basis for mapping the complex by mutagenesis. The 3.1 Å structure of the unliganded enzyme was determined by molecular replacement and refined to 19.9% for all data. Three inserts and one deletion in the coding region are unique to T4TS, and all sites lie on one side of the enzyme surface, possibly encoding unique T4 specific intermolecular interactions during the infective cycle. The crystal structure is generally in the open, unliganded conformation seen in unliganded E. coli TS, as opposed to the closed, ternary complex conformation, except that the critically important C-terminus is inserted into the active site hydrogen bonded to residue Asn85, as seen in functional ternary complex structures. Other differences between E. coli TS and T4TS appear to explain the enhanced binding of folyl polyglutamate to the latter.

Original languageEnglish (US)
Pages (from-to)15459-15468
Number of pages10
JournalBiochemistry
Volume33
Issue number51
DOIs
StatePublished - Dec 1 1994

ASJC Scopus subject areas

  • Biochemistry

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