2b7u
From Proteopedia
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Ribosome inactivating protein type 1 from Charybdis maritima AGG
Overview
A novel, type 1 ribosome-inactivating protein designated charybdin was, isolated from bulbs of Charybdis maritima agg. The protein, consisting of, a single polypeptide chain with a molecular mass of 29 kDa, inhibited, translation in rabbit reticulocytes with an IC50 of 27.2 nm. Plant genomic, DNA extracted from the bulb was amplified by PCR between primers based on, the N-terminal and C-terminal sequence of the protein from dissolved, crystals. The complete mature protein sequence was derived by partial DNA, sequencing and terminal protein sequencing, and was confirmed by, high-resolution crystal structure analysis. The protein contains Val at, position 79 instead of the conserved Tyr residue of the, ribosome-inactivating proteins known to date. To our knowledge, this is, the first observation of a natural substitution of a catalytic residue at, the active site of a natural ribosome-inactivating protein. This, substitution in the active site may be responsible for the relatively low, in vitro translation inhibitory effect compared with other, ribosome-inactivating proteins. Single crystals were grown in the cold, room from PEG6000 solutions. Diffraction data collected to 1.6 A, resolution were used to determine the protein structure by the molecular, replacement method. The fold of the protein comprises two structural, domains: an alpha + beta N-terminal domain (residues 4-190) and a mainly, alpha-helical C-terminal domain (residues 191-257). The active site is, located in the interface between the two domains and comprises residues, Val79, Tyr117, Glu167 and Arg170.
About this Structure
2B7U is a Protein complex structure of sequences from Charybdis maritima with MES as ligand. Active as rRNA N-glycosylase, with EC number 3.2.2.22 Full crystallographic information is available from OCA.
Reference
Isolation, characterization, sequencing and crystal structure of charybdin, a type 1 ribosome-inactivating protein from Charybdis maritima agg., Touloupakis E, Gessmann R, Kavelaki K, Christofakis E, Petratos K, Ghanotakis DF, FEBS J. 2006 Jun;273(12):2684-92. PMID:16817896
Page seeded by OCA on Wed Nov 21 08:37:49 2007
