Structural insights into the protein splicing mechanism of PI-SceI.Poland, B.W., Xu, M.Q., Quiocho, F.A.
(2000) J.Biol.Chem. 275: 16408-16413
- PubMed: 10828056
- PubMed Abstract:
- Protein Splicing Converts the Yeast TFP1 Gene Product to the 69-kD Subunit of the Vacuolar H+-Adenosine Triphosphatase
Kane, P.M.,Yamashiro, C.T.,Wolczyk, D.F.,Neff, N.,Goebl, M.,Stevens, T.H.
(1990) Science 250: 651
- Crystal Structure of PI-SceI, a Homing Endonuclease with Protein Splicing Activity
Duan, X.,Gimble, F.S.,Quiocho, F.A.
(1997) Cell 89: 555
- The chemical basis of protein splicing.
(1998) Chem.Soc.Rev. 27: 375
PI-SceI is a member of a class of proteins (inteins) that excise themselves from a precursor protein and in the process ligate the flanking protein sequences (exteins). We report here the 2.1-A resolution crystal structure of a PI-SceI miniprecursor ...
PI-SceI is a member of a class of proteins (inteins) that excise themselves from a precursor protein and in the process ligate the flanking protein sequences (exteins). We report here the 2.1-A resolution crystal structure of a PI-SceI miniprecursor (VMA29) containing 10 N-terminal extein residues and 4 C-terminal extein residues. Mutations at the N- and C-terminal splicing junctions, blocking in vivo protein splicing, allowed the miniprecursor to be purified and crystallized. The structure reveals both the N- and C-terminal scissile peptide bonds to be in distorted trans conformations (tau approximately 100 degrees ). Modeling of the wild-type PI-SceI based on the VMA29 structure indicates a large conformational change (movement of >9 A) must occur to allow transesterification to be completed. A zinc atom was discovered at the C-terminal splicing junction. Residues Cys(455), His(453), and Glu(80) along with a water molecule (Wat(53)) chelate the zinc atom. The crystal structure of VMA29 has captured the intein in its pre-spliced state.
Howard Hughes Medical Institute and Department of Biochemistry, Baylor College of Medicine, Houston, Texas 77030, USA.