1ynm
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Crystal structure of restriction endonuclease HinP1I
OverviewOverview
HinP1I, a type II restriction endonuclease, recognizes and cleaves a, palindromic tetranucleotide sequence (G/CGC) in double-stranded DNA, producing 2 nt 5' overhanging ends. Here, we report the structure of, HinP1I crystallized as one protein monomer in the crystallographic, asymmetric unit. HinP1I displays an elongated shape, with a conserved, catalytic core domain containing an active-site motif of SDX18QXK and a, putative DNA-binding domain. Without significant sequence homology, HinP1I, displays striking structural similarity to MspI, an endonuclease that, cleaves a similar palindromic DNA sequence (C/CGG) and binds to that, sequence crystallographically as a monomer. Almost all the structural, elements of MspI can be matched in HinP1I, including both the DNA, recognition and catalytic elements. Examining the protein-protein, interactions in the crystal lattice, HinP1I could be dimerized through two, helices located on the opposite side of the protein to the active site, generating a molecule with two active sites and two DNA-binding surfaces, opposite one another on the outer surfaces of the dimer. A possible, functional link between this unusual dimerization mode and the tetrameric, restriction enzymes is discussed.
About this StructureAbout this Structure
1YNM is a Single protein structure of sequence from Haemophilus influenzae. Active as Type II site-specific deoxyribonuclease, with EC number 3.1.21.4 Full crystallographic information is available from OCA.
ReferenceReference
Structure of HinP1I endonuclease reveals a striking similarity to the monomeric restriction enzyme MspI., Yang Z, Horton JR, Maunus R, Wilson GG, Roberts RJ, Cheng X, Nucleic Acids Res. 2005 Apr 1;33(6):1892-901. Print 2005. PMID:15805123
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