1rdb: Difference between revisions
No edit summary |
No edit summary |
||
| Line 5: | Line 5: | ||
|SITE= | |SITE= | ||
|LIGAND= | |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] | |ACTIVITY= <span class='plainlinks'>[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] </span> | ||
|GENE= | |GENE= | ||
|DOMAIN= | |||
|RELATEDENTRY= | |||
|RESOURCES=<span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1rdb FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1rdb OCA], [http://www.ebi.ac.uk/pdbsum/1rdb PDBsum], [http://www.rcsb.org/pdb/explore.do?structureId=1rdb RCSB]</span> | |||
}} | }} | ||
| Line 27: | Line 30: | ||
[[Category: hydrolase(endoribonuclease)]] | [[Category: hydrolase(endoribonuclease)]] | ||
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun Mar 30 23:26:35 2008'' | ||
Revision as of 23:26, 30 March 2008
| |||||||
| , resolution 1.9Å | |||||||
|---|---|---|---|---|---|---|---|
| Activity: | Ribonuclease H, with EC number 3.1.26.4 | ||||||
| Resources: | FirstGlance, OCA, PDBsum, RCSB | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
CRYSTAL STRUCTURES OF RIBONUCLEASE HI ACTIVE SITE MUTANTS FROM ESCHERICHIA COLI
OverviewOverview
In order to investigate the relationships between the three-dimensional structure and the enzymic activity of E. coli RNase HI, three mutant proteins, which were completely inactivated by the replacements of three functional residues, Asp10 by Asn (D10N), Glu48 by Gln (E48Q), and Asp70 by Asn (D70N), were crystallized. Their three-dimensional structures were determined by x-ray crystallography. Although the entire backbone structures of these mutants were not affected by the replacements, very localized conformational changes were observed around the Mg(2+)-binding site. The substitution of an amide group for a negatively charged carboxyl group in common induces the formation of new hydrogen bond networks, presumably due to the cancellation of repulsive forces between carboxyl side chains with negative charges. These conformational changes can account for the loss of the enzymic activity in the mutants, and suggest a possible role for Mg2+ in the hydrolysis. Since the 3 replaced acidic residues are completely conserved in sequences of reverse transcriptases from retroviruses, including human immunodeficiency virus, the concepts of the catalytic mechanism deduced from this structural analysis can also be applied to RNase H activity in reverse transcriptases.
About this StructureAbout this Structure
1RDB is a Single protein structure of sequence from Escherichia coli. Full crystallographic information is available from OCA.
ReferenceReference
Crystal structures of ribonuclease HI active site mutants from Escherichia coli., Katayanagi K, Ishikawa M, Okumura M, Ariyoshi M, Kanaya S, Kawano Y, Suzuki M, Tanaka I, Morikawa K, J Biol Chem. 1993 Oct 15;268(29):22092-9. PMID:8408067
Page seeded by OCA on Sun Mar 30 23:26:35 2008