1ipi
From Proteopedia
| Line 1: | Line 1: | ||
[[Image:1ipi.gif|left|200px]] | [[Image:1ipi.gif|left|200px]] | ||
| - | + | <!-- | |
| - | + | The line below this paragraph, containing "STRUCTURE_1ipi", creates the "Structure Box" on the page. | |
| - | + | You may change the PDB parameter (which sets the PDB file loaded into the applet) | |
| - | + | or the SCENE parameter (which sets the initial scene displayed when the page is loaded), | |
| - | + | or leave the SCENE parameter empty for the default display. | |
| - | + | --> | |
| - | + | {{STRUCTURE_1ipi| PDB=1ipi | SCENE= }} | |
| - | + | ||
| - | + | ||
| - | }} | + | |
'''CRYSTAL STRUCTURE OF THE ARCHAEAL HOLLIDAY JUNCTION RESOLVASE HJC FROM PYROCOCCUS FURIOSUS FORM II''' | '''CRYSTAL STRUCTURE OF THE ARCHAEAL HOLLIDAY JUNCTION RESOLVASE HJC FROM PYROCOCCUS FURIOSUS FORM II''' | ||
| Line 30: | Line 27: | ||
[[Category: Morikawa, K.]] | [[Category: Morikawa, K.]] | ||
[[Category: Nishino, T.]] | [[Category: Nishino, T.]] | ||
| - | [[Category: | + | [[Category: Hjc]] |
| - | [[Category: | + | [[Category: Nuclease fold]] |
| - | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May 2 20:15:37 2008'' | |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | |
Revision as of 17:15, 2 May 2008
CRYSTAL STRUCTURE OF THE ARCHAEAL HOLLIDAY JUNCTION RESOLVASE HJC FROM PYROCOCCUS FURIOSUS FORM II
Overview
Hjc is an archaeal DNA endonuclease, which resolves the Holliday junction in the presence of divalent metals. Combined with mutational analyses, the x-ray structure of the Pyrococcus furiosus Hjc crystal grown in the presence of ammonium sulfate revealed a positively charged interface, rich in conserved basic residues, and the catalytic center (Nishino, T., Komori, K., Tsuchiya, D., Ishino, Y., and Morikawa, K. (2001) Structure 9, 197-T204). This structural study also suggested that the N-terminal segment and some loops of Hjc play crucial roles in the cleavage of DNA. However, a structural view of the interaction between these regions and DNA remains elusive. To clarify the regional roles of Hjc in the recognition of the Holliday junction, further structural and biochemical analyses were carried out. A new crystal form of Hjc was obtained from a polyethylene glycol solution in the absence of ammonium sulfate, and its structure has been determined at 2.16-A resolution. A comparison of the two crystal structures has revealed that the N-terminal segment undergoes a serious conformational change. The site-directed mutagenesis of the sulfate-binding site within the segment caused a dramatic decrease in the junction binding, but the mutant was still capable of cleaving DNA with a 20-fold lower efficiency. The kinetic analysis of Hjc-Holliday junction interaction indicated that mutations in the N-terminal segment greatly increased the dissociation rate constants of the Hjc-Holliday junction complex, explaining the decreased stability of the complex. This segment is also responsible for the disruption of base pairs near the junction center, through specific interactions with them. Taken together, these results imply that, in addition to the secondary effects of two basic loops, the flexible N-terminal segment plays predominant roles in the recognition of DNA conformation near the crossover and in correct positioning of the cleavage site to the catalytic center of the Hjc resolvase.
About this Structure
1IPI is a Single protein structure of sequence from Pyrococcus furiosus. Full crystallographic information is available from OCA.
Reference
Dissection of the regional roles of the archaeal Holliday junction resolvase Hjc by structural and mutational analyses., Nishino T, Komori K, Ishino Y, Morikawa K, J Biol Chem. 2001 Sep 21;276(38):35735-40. Epub 2001 Jul 5. PMID:11441015 Page seeded by OCA on Fri May 2 20:15:37 2008
