1se7
Solution structure of the E. coli bacteriophage P1 encoded HOT protein: a homologue of the theta subunit of E. coli DNA polymerase III
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OverviewOverview
DNA polymerase III, the main replicative polymerase of E. coli, contains a small subunit, theta, that binds to the epsilon proofreading subunit and appears to enhance the enzyme's proofreading function--especially under extreme conditions. It was recently discovered that E. coli bacteriophage P1 encodes a theta homolog, named HOT. The (1)H-(15)N HSQC spectrum of HOT exhibits more uniform intensities and less evidence of conformational exchange than that of theta; this uniformity facilitates a determination of the HOT solution structure by NMR. The structure contains three alpha helices, as reported previously for theta; however, the folding topology of the two proteins is very different. Residual dipolar coupling measurements on labeled theta support the conclusion that it is structurally homologous with HOT. As judged by CD measurements, the melting temperature of HOT was 62 degrees C, compared to 56 degrees C for theta, consistent with other data suggesting greater thermal stability of the HOT protein.
About this StructureAbout this Structure
1SE7 is a Protein complex structure of sequences from Enterobacteria phage p21. Full crystallographic information is available from OCA.
ReferenceReference
Phage like it HOT: solution structure of the bacteriophage P1-encoded HOT protein, a homolog of the theta subunit of E. coli DNA polymerase III., Derose EF, Kirby TW, Mueller GA, Chikova AK, Schaaper RM, London RE, Structure. 2004 Dec;12(12):2221-31. PMID:15576035
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