2ihn
From Proteopedia
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| - | + | {{STRUCTURE_2ihn| PDB=2ihn | SCENE= }} | |
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'''Co-crystal of Bacteriophage T4 RNase H with a fork DNA substrate''' | '''Co-crystal of Bacteriophage T4 RNase H with a fork DNA substrate''' | ||
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[[Category: Mueser, T C.]] | [[Category: Mueser, T C.]] | ||
[[Category: 5'-3' exonuclease]] | [[Category: 5'-3' exonuclease]] | ||
| - | [[Category: | + | [[Category: Bpt4 rnase h]] |
| - | [[Category: | + | [[Category: Fork dna]] |
| - | [[Category: | + | [[Category: Hydrolase/dna complex]] |
| - | + | [[Category: Protein:dna complex]] | |
| - | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun May 4 07:30:58 2008'' | |
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| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | |
Revision as of 04:31, 4 May 2008
Co-crystal of Bacteriophage T4 RNase H with a fork DNA substrate
Overview
Bacteriophage T4 RNase H, a flap endonuclease-1 family nuclease, removes RNA primers from lagging strand fragments. It has both 5' nuclease and flap endonuclease activities. Our previous structure of native T4 RNase H (PDB code 1TFR) revealed an active site composed of highly conserved Asp residues and two bound hydrated magnesium ions. Here, we report the crystal structure of T4 RNase H in complex with a fork DNA substrate bound in its active site. This is the first structure of a flap endonuclease-1 family protein with its complete branched substrate. The fork duplex interacts with an extended loop of the helix-hairpin-helix motif class 2. The 5' arm crosses over the active site, extending below the bridge (helical arch) region. Cleavage assays of this DNA substrate identify a primary cut site 7-bases in from the 5' arm. The scissile phosphate, the first bond in the duplex DNA adjacent to the 5' arm, lies above a magnesium binding site. The less ordered 3' arm reaches toward the C and N termini of the enzyme, which are binding sites for T4 32 protein and T4 45 clamp, respectively. In the crystal structure, the scissile bond is located within the double-stranded DNA, between the first two duplex nucleotides next to the 5' arm, and lies above a magnesium binding site. This complex provides important insight into substrate recognition and specificity of the flap endonuclease-1 enzymes.
About this Structure
2IHN is a Single protein structure of sequence from Enterobacteria phage t4. Full crystallographic information is available from OCA.
Reference
Crystal structure of bacteriophage T4 5' nuclease in complex with a branched DNA reveals how flap endonuclease-1 family nucleases bind their substrates., Devos JM, Tomanicek SJ, Jones CE, Nossal NG, Mueser TC, J Biol Chem. 2007 Oct 26;282(43):31713-24. Epub 2007 Aug 9. PMID:17693399 Page seeded by OCA on Sun May 4 07:30:58 2008
