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rdf:type |
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lifeskim:mentions |
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pubmed:issue |
40
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pubmed:dateCreated |
2003-9-29
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pubmed:databankReference |
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pubmed:abstractText |
We have determined the crystal structure of a 154-residue intein derived from the dnaB gene of Synechocystis sp. strain PCC6803 and refined it to a 2.0-A resolution. The x-ray structure suggests that this intein possesses two catalytic sites that appear to be separately responsible for splicing and cleavage of the N- and C-terminal scissile bonds. The conserved intein block F residues are the important components of a catalytic site for side chain cyclization of the last intein residue, Asn-154. The data suggest that the imidazole ring of His-143 is involved in the activation of the side chain Ndelta atom of Asn-154, leading to a nucleophilic attack on the carbonyl carbon of Asn-154. Substitution of His-143 with Ala or Gln resulted in the inhibition of C-terminal cleavage. His-153, Asp-136, and a water molecule appear to constitute an oxyanion binding site by contacting the carbonyl oxygen of Asn-154 to stabilize the transition state. The structure and mutagenesis data also support that the close contact between the hydroxyl groups of Thr-138 and Ser-155, whose side chain participates in an S --> O acyl shift, plays an important role in the nucleophile orientation. Our structural modeling suggests that this catalytic module is conserved in the C-terminal subdomains of inteins from diverse organisms.
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pubmed:language |
eng
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pubmed:journal |
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pubmed:citationSubset |
IM
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pubmed:chemical |
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pubmed:status |
MEDLINE
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pubmed:month |
Oct
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pubmed:issn |
0021-9258
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pubmed:author |
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pubmed:issnType |
Print
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pubmed:day |
3
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pubmed:volume |
278
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
39133-42
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pubmed:dateRevised |
2006-11-15
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pubmed:meshHeading |
pubmed-meshheading:12878593-Amino Acid Sequence,
pubmed-meshheading:12878593-Asparagine,
pubmed-meshheading:12878593-Aspartic Acid,
pubmed-meshheading:12878593-Bacterial Proteins,
pubmed-meshheading:12878593-Binding Sites,
pubmed-meshheading:12878593-Carbon,
pubmed-meshheading:12878593-Catalysis,
pubmed-meshheading:12878593-Catalytic Domain,
pubmed-meshheading:12878593-Crystallography, X-Ray,
pubmed-meshheading:12878593-Cyanobacteria,
pubmed-meshheading:12878593-DNA Helicases,
pubmed-meshheading:12878593-DnaB Helicases,
pubmed-meshheading:12878593-Genetic Vectors,
pubmed-meshheading:12878593-Histidine,
pubmed-meshheading:12878593-Models, Chemical,
pubmed-meshheading:12878593-Models, Genetic,
pubmed-meshheading:12878593-Models, Molecular,
pubmed-meshheading:12878593-Molecular Sequence Data,
pubmed-meshheading:12878593-Oxygen,
pubmed-meshheading:12878593-Peptides,
pubmed-meshheading:12878593-Protein Conformation,
pubmed-meshheading:12878593-Protein Splicing,
pubmed-meshheading:12878593-Protein Structure, Tertiary,
pubmed-meshheading:12878593-RNA Splicing,
pubmed-meshheading:12878593-Sequence Homology, Amino Acid,
pubmed-meshheading:12878593-Structure-Activity Relationship,
pubmed-meshheading:12878593-Water
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pubmed:year |
2003
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pubmed:articleTitle |
Crystal structure of a mini-intein reveals a conserved catalytic module involved in side chain cyclization of asparagine during protein splicing.
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pubmed:affiliation |
Laboratory of Structural Biology and the Ministry of Education Laboratory of Protein Science, School of Life Science and Engineering, Tsinghua University, Beijing 100084, People's Republic of China.
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pubmed:publicationType |
Journal Article,
Research Support, Non-U.S. Gov't
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