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| - | [[Image:1zm8.gif|left|200px]] | + | {{Seed}} |
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| | {{STRUCTURE_1zm8| PDB=1zm8 | SCENE= }} | | {{STRUCTURE_1zm8| PDB=1zm8 | SCENE= }} |
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| - | '''Apo Crystal structure of Nuclease A from Anabaena sp.'''
| + | ===Apo Crystal structure of Nuclease A from Anabaena sp.=== |
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| - | ==Overview==
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| - | Nuclease A (NucA) is a nonspecific endonuclease from Anabaena sp. capable of degrading single- and double-stranded DNA and RNA in the presence of divalent metal ions. We have determined the structure of the delta(2-24),D121A mutant of NucA in the presence of Zn2+ and Mn2+ (PDB code 1ZM8). The mutations were introduced to remove the N-terminal signal peptide and to reduce the activity of the nonspecific nuclease, thereby reducing its toxicity to the Escherichia coli expression system. NucA contains a betabeta alpha metal finger motif and a hydrated Mn2+ ion at the active site. Unexpectedly, NucA was found to contain additional metal binding sites approximately 26 A apart from the catalytic metal binding site. A structural comparison between NucA and the closest analog for which structural data exist, the Serratia nuclease, indicates several interesting differences. First, NucA is a monomer rather than a dimer. Second, there is an unexpected structural homology between the N-terminal segments despite a poorly conserved sequence, which in Serratia includes a cysteine bridge thought to play a regulatory role. In addition, although a sequence alignment had suggested that NucA lacks a proposed catalytic residue corresponding to Arg57 in Serratia, the structure determined here indicates that Arg93 in NucA is positioned to fulfill this role. Based on comparison with DNA-bound nuclease structures of the betabeta alpha metal finger nuclease family and available mutational data on NucA, we propose that His124 acts as a catalytic base, and Arg93 participates in the catalysis possibly through stabilization of the transition state.
| + | The line below this paragraph, {{ABSTRACT_PUBMED_15897201}}, adds the Publication Abstract to the page |
| | + | (as it appears on PubMed at http://www.pubmed.gov), where 15897201 is the PubMed ID number. |
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| | + | {{ABSTRACT_PUBMED_15897201}} |
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| | ==About this Structure== | | ==About this Structure== |
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| | [[Category: Nuca]] | | [[Category: Nuca]] |
| | [[Category: Nuclease]] | | [[Category: Nuclease]] |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May 3 17:47:58 2008'' | + | |
| | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Mon Jul 28 05:16:41 2008'' |
Revision as of 02:16, 28 July 2008
Template:STRUCTURE 1zm8
Apo Crystal structure of Nuclease A from Anabaena sp.
Template:ABSTRACT PUBMED 15897201
About this Structure
1ZM8 is a Single protein structure of sequence from Anabaena sp.. Full crystallographic information is available from OCA.
Reference
Structural insights into the mechanism of nuclease A, a betabeta alpha metal nuclease from Anabaena., Ghosh M, Meiss G, Pingoud A, London RE, Pedersen LC, J Biol Chem. 2005 Jul 29;280(30):27990-7. Epub 2005 May 15. PMID:15897201
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