From Proteopedia
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| | {{STRUCTURE_2oqa| PDB=2oqa | SCENE= }} | | {{STRUCTURE_2oqa| PDB=2oqa | SCENE= }} |
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| - | '''X-ray Sequence and Crystal Structure of Luffaculin 1, a Novel Type 1 Ribosome-inactivating Protein'''
| + | ===X-ray Sequence and Crystal Structure of Luffaculin 1, a Novel Type 1 Ribosome-inactivating Protein=== |
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| - | ==Overview==
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| - | BACKGROUND: Protein sequence can be obtained through Edman degradation, mass spectrometry, or cDNA sequencing. High resolution X-ray crystallography can also be used to derive protein sequence information, but faces the difficulty in distinguishing the Asp/Asn, Glu/Gln, and Val/Thr pairs. Luffaculin 1 is a new type 1 ribosome-inactivating protein (RIP) isolated from the seeds of Luffa acutangula. Besides rRNA N-glycosidase activity, luffaculin 1 also demonstrates activities including inhibiting tumor cells' proliferation and inducing tumor cells' differentiation. RESULTS: The crystal structure of luffaculin 1 was determined at 1.4 A resolution. Its amino-acid sequence was derived from this high resolution structure using the following criteria: 1) high resolution electron density; 2) comparison of electron density between two molecules that exist in the same crystal; 3) evaluation of the chemical environment of residues to break down the sequence assignment ambiguity in residue pairs Glu/Gln, Asp/Asn, and Val/Thr; 4) comparison with sequences of the homologous proteins. Using the criteria 1 and 2, 66% of the residues can be assigned. By incorporating with criterion 3, 86% of the residues were assigned, suggesting the effectiveness of chemical environment evaluation in breaking down residue ambiguity. In total, 94% of the luffaculin 1 sequence was assigned with high confidence using this improved X-ray sequencing strategy. Two N-acetylglucosamine moieties, linked respectively to the residues Asn77 and Asn84, can be identified in the structure. Residues Tyr70, Tyr110, Glu159 and Arg162 define the active site of luffaculin 1 as an RNA N-glycosidase. CONCLUSION: X-ray sequencing method can be effective to derive sequence information of proteins. The evaluation of the chemical environment of residues is a useful method to break down the assignment ambiguity in Glu/Gln, Asp/Asn, and Val/Thr pairs. The sequence and the crystal structure confirm that luffaculin 1 is a new type 1 RIP.
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| | + | (as it appears on PubMed at http://www.pubmed.gov), where 17470286 is the PubMed ID number. |
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| | + | {{ABSTRACT_PUBMED_17470286}} |
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| | ==About this Structure== | | ==About this Structure== |
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| | [[Category: Huang, M.]] | | [[Category: Huang, M.]] |
| | [[Category: Mixed alpha helix and beta sheet]] | | [[Category: Mixed alpha helix and beta sheet]] |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun May 4 11:26:31 2008'' | + | |
| | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Mon Jul 28 18:08:16 2008'' |
Revision as of 15:08, 28 July 2008
Template:STRUCTURE 2oqa
X-ray Sequence and Crystal Structure of Luffaculin 1, a Novel Type 1 Ribosome-inactivating Protein
Template:ABSTRACT PUBMED 17470286
About this Structure
Full crystallographic information is available from OCA.
Reference
X-ray sequence and crystal structure of luffaculin 1, a novel type 1 ribosome-inactivating protein., Hou X, Chen M, Chen L, Meehan EJ, Xie J, Huang M, BMC Struct Biol. 2007 Apr 30;7:29. PMID:17470286
Page seeded by OCA on Mon Jul 28 18:08:16 2008
