2pqi
From Proteopedia
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Crystal structure of active ribosome inactivating protein from maize (b-32)
Overview
Maize ribosome-inactivating protein is classified as a class III or an, atypical RNA N-glycosidase. It is synthesized as an inactive precursor, with a 25-amino acid internal inactivation region, which is removed in the, active form. As the first structural example of this class of proteins, crystals of the precursor and the active form were diffracted to 2.4 and, 2.5 A, respectively. The two proteins are similar, with main chain root, mean square deviation (RMSD) of 0.519. In the precursor, the inactivation, region is found on the protein surface and consists of a flexible loop, followed by a long alpha-helix. This region diminished both the, interaction with ribosome and cytotoxicity, but not cellular uptake. Like, bacterial ribosome-inactivating proteins, maize ribosome-inactivating, protein does not have a back-up glutamate in the active site, which helps, the protein to retain some activity if the catalytic glutamate is mutated., The structure reveals that the active site is too small to accommodate two, glutamate residues. Our structure suggests that maize, ribosome-inactivating protein may represent an intermediate product in the, evolution of ribosome-inactivating proteins.
About this Structure
2PQI is a Single protein structure of sequence from Zea mays. Active as rRNA N-glycosylase, with EC number 3.2.2.22 Full crystallographic information is available from OCA.
Reference
Structure-function study of maize ribosome-inactivating protein: implications for the internal inactivation region and the sole glutamate in the active site., Mak AN, Wong YT, An YJ, Cha SS, Sze KH, Au SW, Wong KB, Shaw PC, Nucleic Acids Res. 2007;35(18):6259-67. Epub 2007 Sep 13. PMID:17855394
Page seeded by OCA on Wed Feb 13 08:20:22 2008
