BACILLUS FRAGMENT (BF) IS THE C-TERMINAL 592 AMINO ACIDS OF THE WILD TYPE BACILLUS DNA POLYMERASE. ...BACILLUS FRAGMENT (BF) IS THE C-TERMINAL 592 AMINO ACIDS OF THE WILD TYPE BACILLUS DNA POLYMERASE. THIS POLYMERASE RETAINS POLYMERASE ACTIVITY BUT LACKS ALL EXONUCLEASE ACTIVITY. BF IS A THERMOSTABLE ENZYME AND HAS AN OPTIMAL TEMPERATURE FOR ACTIVITY OF 65 DEGREES CELSIUS. THE PROTEIN IS HOMOLOGOUS TO ESCHERICHIA COLI DNA POLYMERASE I AND THERMUS AQUATICUS (TAQ) DNA POLYMERASE. THE SECONDARY STRUCTURAL ELEMENTS OF THE ENZYME HAVE BEEN ASSIGNED USING THE KABSCH AND SANDER ALGORITHM ENCODED IN PROCHECK AND THEN WERE NAMED TO BE CONSISTENT WITH THE STRUCTURE OF THE KLENOW FRAGMENT (KF) OF ESCHERICHIA COLI DNA POLYMERASE I. IN THE FOLLOWING TOPOLOGY ASSIGNMENT, HELICES ARE INDICATED AS CAPITAL LETTERS AND SHEETS ARE REPRESENTED BY NUMBERS. THE RESIDUE RANGE COVERED BY THE SECONDARY STRUCTURE ELEMENT IS SHOWN IN PARENTHESES. LETTERS AND NUMBERS FOLLOWING THE INITIAL LETTERS INDICATE ELEMENTS FOUND IN THE REFINED KF STRUCTURES OR ONLY IN THIS STRUCTURE. VESTIGIAL EXONUCLEASE DOMAIN: 1 (302 - 304), A (308 - 312), 2 (314 - 321), 3 (334 - 339), 4 (342 - 346), A1 (347 - 353), B (354 - 363), 5 (367 - 370), C (372 - 382), 5A (389 - 393), D (394 - 402), E(409-416), E1 (424 - 430), F (439 - 468); POLYMERASE DOMAIN: G (470 - 477), G1 (478 - 492), 6 (493 - 495), H (496 - 522), H1 (530 - 540), H2 (557 - 565), I (568 - 588), I1 (589 - 595), 6A (600 - 602), 7 (605 - 607), 8 (617 - 619), J (622 - 626), K (633 - 638), 8A (639 - 641), 9 (646 - 655), L (656 - 667), M (668 - 677), N (680 - 691), N1 (693 - 697), O (698 - 714), O1 (717 - 726), O2 (728 - 743), P (744 - 761), 10 (762 - 765), 11 (769 - 773), P1 (774 - 778), Q (780 - 818), 12 (823 - 828), 13 (830 - 838), R (840 - 854), 14 (863 - 869), S (871 - 876)