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Crystal structures of open and closed forms of binary and ternary complexes of the large fragment of Thermus aquaticus DNA polymerase I: structural basis for nucleotide incorporation
Author(s) -
Li Ying,
Korolev Sergey,
Waksman Gabriel
Publication year - 1998
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1093/emboj/17.24.7514
Subject(s) - thermus aquaticus , ternary complex , biology , dna polymerase , primer (cosmetics) , polymerase , ternary operation , dna , thermus thermophilus , crystallography , dna polymerase i , nucleotide , biophysics , biochemistry , microbiology and biotechnology , enzyme , chemistry , polymerase chain reaction , escherichia coli , reverse transcriptase , computer science , gene , programming language , organic chemistry
The crystal structures of two ternary complexes of the large fragment of Thermus aquaticus DNA polymerase I (Klentaq1) with a primer/template DNA and dideoxycytidine triphosphate, and that of a binary complex of the same enzyme with a primer/template DNA, were determined to a resolution of 2.3, 2.3 and 2.5 Å, respectively. One ternary complex structure differs markedly from the two other structures by a large reorientation of the tip of the fingers domain. This structure, designated ‘closed’, represents the ternary polymerase complex caught in the act of incorporating a nucleotide. In the two other structures, the tip of the fingers domain is rotated outward by 46° (‘open’) in an orientation similar to that of the apo form of Klentaq1. These structures provide the first direct evidence in DNA polymerase I enzymes of a large conformational change responsible for assembling an active ternary complex.