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Search The CSA
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Catalytic Site Atlas

CSA LITERATURE entry for 1lws

E.C. nameH+-transporting two-sector ATPase
SpeciesSaccharomyces cerevisiae (Baker's yeast)
E.C. Number (IntEnz) 3.6.3.14
CSA Homologues of 1lws1dfa,1dq3,1ef0,1jva,1lwt,1um2,1vde,2cw7,2dch,
CSA Entries With UniProtID P17255
CSA Entries With EC Number 3.6.3.14
PDBe Entry 1lws
PDBSum Entry 1lws
MACiE Entry 1lws

Literature Report

IntroductionThe homing endonuclease from S. cerevisiae, PI-SceI is able to catalyse the specific cleavage of double stranded DNA in order to allow the incorporation of a mobile intron into the allele. This enables non-mendelian propagation of certain introns without harming the target allele, as the introns are spliced out before functional mRNA is produced. It belongs to a large family of endonucleases all with the sequence LADLIDADG, and contains two active sites to allow simultaneous cleavage of both strands of DNA. The homing endonucleases in general are highly specific, and PI-SceI thus recognises a 31 base pair DNA sequence as its substrate, the longest specific sequence for a DNA binding protein yet discovered. This entry covers the active site which cleaves the top strand, running 5' to 3'.
MechansimThe cleavage of double stranded DNA occurs by nucleophilic attack from a water molecule activated by a Mg2+ ion at the active site on the phosphate to give a pentavalent phosphate transition state, stabilised by contact to the Mg2+ ion. Protonation of the 3' deoxyribose sugar by Lys 403 allows the cleavage of the backbone to release the two fragments.
Reaction

Catalytic Sites for 1lws

Annotated By Reference To The Literature - Site 1 (Perform Site Search)
ResidueChainNumberUniProtKB NumberFunctional PartFunctionTargetDescription
LysA403686macie:sideChainProtonates the leaving group, facilitating collapse of the pentavalent phosphate transition state.

Annotated By Reference To The Literature - Site 2 (Perform Site Search)
ResidueChainNumberUniProtKB NumberFunctional PartFunctionTargetDescription
LysA301584macie:sideChainProtonates the leaving group to enable collapse of the pentavalent phosphate transition state liberating the product.

Literature References

Notes:
Schöttler S
Identification of Asp218 and Asp326 as the principal Mg2+ binding ligands of the homing endonuclease PI-SceI.
Biochemistry 2000 39 15895-15900
PubMed: 11123916
Moure CM
Crystal structure of the intein homing endonuclease PI-SceI bound to its recognition sequence.
Nat Struct Biol 2002 9 764-770
PubMed: 12219083
Christ F
The monomeric homing endonuclease PI-SceI has two catalytic centres for cleavage of the two strands of its DNA substrate.
EMBO J 1999 18 6908-6916
PubMed: 10601013
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