1goc: Difference between revisions
No edit summary |
No edit summary |
||
| Line 1: | Line 1: | ||
[[Image:1goc.gif|left|200px]] | [[Image:1goc.gif|left|200px]] | ||
'''COOPERATIVE STABILIZATION OF ESCHERICHIA COLI RIBONUCLEASE HI BY INSERTION OF GLY-80B AND GLY-77-> ALA SUBSTITUTION''' | {{Structure | ||
|PDB= 1goc |SIZE=350|CAPTION= <scene name='initialview01'>1goc</scene>, resolution 2.0Å | |||
|SITE= | |||
|LIGAND= | |||
|ACTIVITY= [http://en.wikipedia.org/wiki/Ribonuclease_H Ribonuclease H], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.1.26.4 3.1.26.4] | |||
|GENE= | |||
}} | |||
'''COOPERATIVE STABILIZATION OF ESCHERICHIA COLI RIBONUCLEASE HI BY INSERTION OF GLY-80B AND GLY-77-> ALA SUBSTITUTION''' | |||
==Overview== | ==Overview== | ||
| Line 7: | Line 16: | ||
==About this Structure== | ==About this Structure== | ||
1GOC is a [ | 1GOC is a [[Single protein]] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1GOC OCA]. | ||
==Reference== | ==Reference== | ||
Cooperative stabilization of Escherichia coli ribonuclease HI by insertion of Gly-80b and Gly-77-->Ala substitution., Ishikawa K, Nakamura H, Morikawa K, Kimura S, Kanaya S, Biochemistry. 1993 Jul 20;32(28):7136-42. PMID:[http:// | Cooperative stabilization of Escherichia coli ribonuclease HI by insertion of Gly-80b and Gly-77-->Ala substitution., Ishikawa K, Nakamura H, Morikawa K, Kimura S, Kanaya S, Biochemistry. 1993 Jul 20;32(28):7136-42. PMID:[http://www.ncbi.nlm.nih.gov/pubmed/8393706 8393706] | ||
[[Category: Escherichia coli]] | [[Category: Escherichia coli]] | ||
[[Category: Ribonuclease H]] | [[Category: Ribonuclease H]] | ||
| Line 21: | Line 30: | ||
[[Category: hydrolase(endoribonuclease)]] | [[Category: hydrolase(endoribonuclease)]] | ||
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Mar 20 11:25:48 2008'' | ||
Revision as of 12:25, 20 March 2008
| |||||||
| , resolution 2.0Å | |||||||
|---|---|---|---|---|---|---|---|
| Activity: | Ribonuclease H, with EC number 3.1.26.4 | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
COOPERATIVE STABILIZATION OF ESCHERICHIA COLI RIBONUCLEASE HI BY INSERTION OF GLY-80B AND GLY-77-> ALA SUBSTITUTION
OverviewOverview
The insertion of a Gly residue (designated as Gly-80b) between the C-cap of the alpha II-helix (Gln-80) and the N-cap of the alpha III-helix (Trp-81) in Escherichia coli ribonuclease HI enhances the protein stability by 0.4 kcal/mol in delta G (Kimura, S., Nakamura, H., Hashimoto, T., Oobatake, M., & Kanaya, S. (1992) J. Biol. Chem. 267, 21535-21542). Another mutation within the alpha II-helix, Gly-77-->Ala, reduces the stability by 0.9 kcal/mol. Simultaneous introduction of these mutations enhances the stability by 0.8 kcal/mol, indicating that the effects of these mutations are cooperative and not simply independent. We determined the crystal structures of these three mutant proteins (G80b-, A77-, and A77/G80b-RNase H) to investigate this cooperative mechanism of the protein stabilization. The structures revealed that the inserted Gly-80b assumes a left-handed helical conformation in both the G80b- and the A77/G80b-RNase H. This inserted glycine residue allows the formation of a "paperclip", which is a common motif at the C-termini of alpha-helices. Accompanying the formation of the paperclip motif, two intrahelical hydrogen bonds are formed between the backbone atoms (O78-N80b and O80b-N84). The stabilization caused by the insertion of Gly-80b can be ascribed to the formation of these hydrogen bonds. The Gly-77-->Ala substitution destabilizes the protein due to the deformed packing interactions in the hydrophobic core around Ala-77 and the stress in the wedged indole ring of Trp-81. These effects are alleviated by the insertion of Gly-80b, which relaxes the backbone structure.(ABSTRACT TRUNCATED AT 250 WORDS)
About this StructureAbout this Structure
1GOC is a Single protein structure of sequence from Escherichia coli. Full crystallographic information is available from OCA.
ReferenceReference
Cooperative stabilization of Escherichia coli ribonuclease HI by insertion of Gly-80b and Gly-77-->Ala substitution., Ishikawa K, Nakamura H, Morikawa K, Kimura S, Kanaya S, Biochemistry. 1993 Jul 20;32(28):7136-42. PMID:8393706
Page seeded by OCA on Thu Mar 20 11:25:48 2008