3NT8: Crystal Structure Of Na-Asp-1

Citation:
Abstract
Major proteins secreted by the infective larval stage hookworms upon host entry include Ancylostoma secreted proteins (ASPs), which are characterized by one or two CAP (cysteine-rich secretory protein/antigen 5/pathogenesis related-1) domains. The CAP domain has been reported in diverse phylogenetically unrelated proteins, but has no confirmed function. The first structure of a two-CAP-domain protein, Na-ASP-1, from the major human hookworm parasite Necator americanus was refined to a resolution limit of 2.2 A. The structure was solved by molecular replacement (MR) using Na-ASP-2, a one-CAP-domain ASP, as the search model. The correct MR solution could only be obtained by truncating the polyalanine model of Na-ASP-2 and removing several loops. The structure reveals two CAP domains linked by an extended loop. Overall, the carboxyl-terminal CAP domain is more similar to Na-ASP-2 than to the amino-terminal CAP domain. A large central cavity extends from the amino-terminal CAP domain to the carboxyl-terminal CAP domain, encompassing the putative CAP-binding cavity. The putative CAP-binding cavity is a characteristic cavity in the carboxyl-terminal CAP domain that contains a His and Glu pair. These residues are conserved in all single-CAP-domain proteins, but are absent in the amino-terminal CAP domain. The conserved His residues are oriented such that they appear to be capable of directly coordinating a zinc ion as observed for CAP proteins from reptile venoms. This first structure of a two-CAP-domain ASP can serve as a template for homology modeling of other two-CAP-domain proteins.
PDB ID: 3NT8Download
MMDB ID: 90155
PDB Deposition Date: 2010/7/2
Updated in MMDB: 2011/05
Experimental Method:
x-ray diffraction
Resolution: 2.2  Å
Source Organism:
Similar Structures:
Biological Unit for 3NT8: monomeric; determined by author and by software (PISA)
Molecular Components in 3NT8
Label Count Molecule
Protein (1 molecule)
1
Ancylostoma Secreted Protein 1
Molecule annotation
* Click molecule labels to explore molecular sequence information.

Citing MMDB
.