Crystal Structure of the Cysteine-rich Secretory Protein Stecrisp Reveals That the Cysteine-rich Domain Has a K+ Channel Inhibitor-like Fold

Cornell University, Итак, New York, United States
Journal of Biological Chemistry (Impact Factor: 4.57). 05/2005; 280(13):12405-12. DOI: 10.1074/jbc.M413566200
Source: PubMed


Stecrisp from Trimeresurus stejnegeri snake venom belongs to a family of cysteine-rich secretory proteins (CRISP) that have various functions related to sperm-egg
fusion, innate host defense, and the blockage of ion channels. Here we present the crystal structure of stecrisp refined to
1.6-Å resolution. It shows that stecrisp contains three regions, namely a PR-1 (pathogenesis-related proteins of group1) domain, a hinge, and a cysteine-rich domain (CRD). A conformation of solvent-exposed and -conserved residues (His60, Glu75, Glu96, and His115) in the PR-1 domain similar to that of their counterparts in homologous structures suggests they may share some molecular
mechanism. Three flexible loops of hypervariable sequence surrounding the possible substrate binding site in the PR-1 domain
show an evident difference in homologous structures, implying that a great diversity of species- and substrate-specific interactions
may be involved in recognition and catalysis. The hinge is fixed by two crossed disulfide bonds formed by four of ten characteristic
cysteines in the carboxyl-terminal region and is important for stabilizing the N-terminal PR-1 domain. Spatially separated
from the PR-1 domain, CRD possesses a similar fold with two K+ channel inhibitors (Bgk and Shk). Several candidates for the possible functional sites of ion channel blocking are located
in a solvent-exposed loop in the CRD. The structure of stecrisp will provide a prototypic architecture for a structural and
functional exploration of the diverse members of the CRISP family.

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Available from: Min Guo, Nov 12, 2015
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    • "Ion channel regulatory activity described mainly in reptile venoms performed by ICR region; inhibition of Ca 2+ , K + , cyclic nucleotide-gated channels (Guo et al., 2005; Nobile et al., 1996; Shikamoto et al., 2005; Suzuki et al., 2008; Wang et al., 2006). Modulation of pro-inflammatory processes via Zn 2+ and heparan sulfate-dependent transcription regulation in reptile venoms performed by CAP domain (Wang et al., 2010). "
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    • "Annotation and fold appraisal was guided by results from automated model predictions performed with I-TASSER (Yang et al., 2015). Using PSIPRED (Bryson et al., 2005) secondary structure predictions for inferred H. contortus CAP proteins, structure-based amino acid sequence alignments were made using SBAL (Wang et al., 2012; Wang and Hofmann, 2015), and the amino acid sequence of SteCRISP was added using the crystal structure deposited in PDB entry 1rc9 (Guo et al., 2005). In preparation for comparative modelling of Hc-CAP-15, SteCRISP was identified as the most suitable template (P-value: 2x10 -6 ) by surveying the PDB with pGenThreader (Bryson et al., 2005) for the protein with highest homology. "
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    • "ShK domains are common in the astacin family of metalloendopeptidases, which includes BMP1/Tolloid, meprins, and MMP23 as examples. The ShK motif in astacins is thought to mediate protein-protein interactions [65]. "
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