From Proteopedia
(Difference between revisions)
proteopedia linkproteopedia link
|
|
| Line 1: |
Line 1: |
| - | [[Image:1em8.gif|left|200px]] | + | {{Seed}} |
| | + | [[Image:1em8.png|left|200px]] |
| | | | |
| | <!-- | | <!-- |
| Line 9: |
Line 10: |
| | {{STRUCTURE_1em8| PDB=1em8 | SCENE= }} | | {{STRUCTURE_1em8| PDB=1em8 | SCENE= }} |
| | | | |
| - | '''Crystal structure of chi and psi subunit heterodimer from DNA POL III'''
| + | ===Crystal structure of chi and psi subunit heterodimer from DNA POL III=== |
| | | | |
| | | | |
| - | ==Overview==
| + | <!-- |
| - | The chi (chi) and psi (psi) subunits of Escherichia coli DNA polymerase III form a heterodimer that is associated with the ATP-dependent clamp-loader machinery. In E. coli, the chi:psi heterodimer serves as a bridge between the clamp-loader complex and the single-stranded DNA-binding protein. We determined the crystal structure of the chi:psi heterodimer at 2.1 A resolution. Although neither chi (147 residues) nor psi (137 residues) bind to nucleotides, the fold of each protein is similar to the folds of mononucleotide-(chi) or dinucleotide-(psi) binding proteins, without marked similarity to the structures of the clamp-loader subunits. Genes encoding chi and psi proteins are found to be readily identifiable in several bacterial genomes and sequence alignments showed that residues at the chi:psi interface are highly conserved in both proteins, suggesting that the heterodimeric interaction is of functional significance. The conservation of surface-exposed residues is restricted to the interfacial region and to just two other regions in the chi:psi complex. One of the conserved regions was found to be located on chi, distal to the psi interaction region, and we identified this as the binding site for a C-terminal segment of the single-stranded DNA-binding protein. The other region of sequence conservation is localized to an N-terminal segment of psi (26 residues) that is disordered in the crystal structure. We speculate that psi is linked to the clamp-loader complex by this flexible, but conserved, N-terminal segment, and that the chi:psi unit is linked to the single-stranded DNA-binding protein via the distal surface of chi. The base of the clamp-loader complex has an open C-shaped structure, and the shape of the chi:psi complex is suggestive of a loose docking within the crevice formed by the open faces of the delta and delta' subunits of the clamp-loader. | + | The line below this paragraph, {{ABSTRACT_PUBMED_14717711}}, adds the Publication Abstract to the page |
| | + | (as it appears on PubMed at http://www.pubmed.gov), where 14717711 is the PubMed ID number. |
| | + | --> |
| | + | {{ABSTRACT_PUBMED_14717711}} |
| | | | |
| | ==About this Structure== | | ==About this Structure== |
| Line 31: |
Line 35: |
| | [[Category: Dna pol iii]] | | [[Category: Dna pol iii]] |
| | [[Category: Heterodimer]] | | [[Category: Heterodimer]] |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May 2 15:16:12 2008'' | + | |
| | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Tue Jul 1 00:58:25 2008'' |
Revision as of 21:58, 30 June 2008
Template:STRUCTURE 1em8
Crystal structure of chi and psi subunit heterodimer from DNA POL III
Template:ABSTRACT PUBMED 14717711
About this Structure
1EM8 is a Protein complex structure of sequences from Escherichia coli. Full crystallographic information is available from OCA.
Reference
Crystal structure of the chi:psi sub-assembly of the Escherichia coli DNA polymerase clamp-loader complex., Gulbis JM, Kazmirski SL, Finkelstein J, Kelman Z, O'Donnell M, Kuriyan J, Eur J Biochem. 2004 Jan;271(2):439-49. PMID:14717711
Page seeded by OCA on Tue Jul 1 00:58:25 2008
