1xo1
From Proteopedia
| Line 1: | Line 1: | ||
[[Image:1xo1.jpg|left|200px]] | [[Image:1xo1.jpg|left|200px]] | ||
| - | + | <!-- | |
| - | + | The line below this paragraph, containing "STRUCTURE_1xo1", 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_1xo1| PDB=1xo1 | SCENE= }} |
| - | + | ||
| - | + | ||
| - | }} | + | |
'''T5 5'-EXONUCLEASE MUTANT K83A''' | '''T5 5'-EXONUCLEASE MUTANT K83A''' | ||
| Line 24: | Line 21: | ||
Mutagenesis of conserved lysine residues in bacteriophage T5 5'-3' exonuclease suggests separate mechanisms of endo-and exonucleolytic cleavage., Garforth SJ, Ceska TA, Suck D, Sayers JR, Proc Natl Acad Sci U S A. 1999 Jan 5;96(1):38-43. PMID:[http://www.ncbi.nlm.nih.gov/pubmed/9874768 9874768] | Mutagenesis of conserved lysine residues in bacteriophage T5 5'-3' exonuclease suggests separate mechanisms of endo-and exonucleolytic cleavage., Garforth SJ, Ceska TA, Suck D, Sayers JR, Proc Natl Acad Sci U S A. 1999 Jan 5;96(1):38-43. PMID:[http://www.ncbi.nlm.nih.gov/pubmed/9874768 9874768] | ||
[[Category: Enterobacteria phage t5]] | [[Category: Enterobacteria phage t5]] | ||
| - | [[Category: Exodeoxyribonuclease (lambda-induced)]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Ceska, T A.]] | [[Category: Ceska, T A.]] | ||
[[Category: Sayers, J R.]] | [[Category: Sayers, J R.]] | ||
[[Category: Suck, D.]] | [[Category: Suck, D.]] | ||
| - | [[Category: | + | [[Category: Exonuclease]] |
| - | [[Category: | + | [[Category: Hydrolase]] |
| - | [[Category: | + | [[Category: Nuclease]] |
| - | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May 3 15:16:57 2008'' | |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | |
Revision as of 12:16, 3 May 2008
T5 5'-EXONUCLEASE MUTANT K83A
Overview
Efficient cellular DNA replication requires the activity of a 5'-3' exonuclease. These enzymes are able to hydrolyze DNA.DNA and RNA.DNA substrates exonucleolytically, and they are structure-specific endonucleases. The 5'-3' exonucleases are conserved in organisms as diverse as bacteriophage and mammals. Crystal structures of three representative enzymes identify two divalent-metal-binding sites typically separated by 8-10 A. Site-directed mutagenesis was used to investigate the roles of three lysine residues (K83, K196, and K215) situated near two metal-binding sites in bacteriophage T5 5'-3' exonuclease. Neither K196 nor K215 was essential for either the exo- or the endonuclease activity, but mutation of these residues increased the dissociation constant for the substrate from 5 nM to 200 nM (K196A) and 50 nM (K215A). Biochemical analysis demonstrated that K83 is absolutely required for exonucleolytic activity on single-stranded DNA but is not required for endonucleolytic cleavage of flap structures. Structural analysis of this mutant by x-ray crystallography showed no significant perturbations around the metal-binding sites in the active site. The wild-type protein has different pH optima for endonuclease and exonuclease activities. Taken together, these results suggest that different mechanisms for endo- and exonucleolytic hydrolysis are used by this multifunctional enzyme.
About this Structure
1XO1 is a Single protein structure of sequence from Enterobacteria phage t5. Full crystallographic information is available from OCA.
Reference
Mutagenesis of conserved lysine residues in bacteriophage T5 5'-3' exonuclease suggests separate mechanisms of endo-and exonucleolytic cleavage., Garforth SJ, Ceska TA, Suck D, Sayers JR, Proc Natl Acad Sci U S A. 1999 Jan 5;96(1):38-43. PMID:9874768 Page seeded by OCA on Sat May 3 15:16:57 2008
