PDBsum entry 1fiz

Hydrolase

PDB id: 1fiz

Contents

Protein chains

263 a.a. *

13 a.a. *

Ligands

NAG-NDG-BMA-FUL

SO4 ×4

PBZ

Waters ×25

* Residue conservation analysis

PDB id:

1fiz

Name:

Hydrolase

Title:

Three dimensional structure of beta-acrosin from boar spermatozoa

Structure:

Beta-acrosin heavy chain. Chain: a. Beta-acrosin light chain. Chain: l

Source:

Sus scrofa. Pig. Organism_taxid: 9823. Organ: testis. Cell: spermatozoa. Cell: spermatozoa

Biol. unit:

Dimer (from PQS)

Resolution:

2.90Å R-factor: 0.212 R-free: 0.265

Authors:

R.Tranter,J.A.Read,R.Jones,R.L.Brady

Key ref:

R.Tranter et al. (2000). Effector sites in the three-dimensional structure of mammalian sperm beta-acrosin. Structure, 8, 1179-1188. PubMed id: 11080640 DOI: 10.1016/S0969-2126(00)00523-2

Date:

07-Aug-00 Release date: 08-Nov-00

Protein chain

P08001  (ACRO_PIG) -  Acrosin from Sus scrofa

Seq: 415 a.a.

Struc: 263 a.a.

Protein chain

P08001  (ACRO_PIG) -  Acrosin from Sus scrofa

Seq: 415 a.a.

Struc: 13 a.a.

Enzyme reactions

• Enzyme class: Chains A, L: E.C.3.4.21.10 - acrosin.
• Reaction: Hydrolysis of Arg-|-Xaa and Lys-|-Xaa bonds; preferential cleavage Arg-|-Xaa >> Lys-|-Lys >> Lys-|-Xaa.

DOI no: 10.1016/S0969-2126(00)00523-2

Structure 8:1179-1188 (2000)

PubMed id: 11080640

Effector sites in the three-dimensional structure of mammalian sperm beta-acrosin.

R.Tranter, J.A.Read, R.Jones, R.L.Brady.

ABSTRACT

BACKGROUND: Proacrosin is a serine protease found specifically within the acrosomal vesicle of all mammalian spermatozoa. During fertilization proacrosin autoactivates to form beta-acrosin, in which there is a "light" chain cross-linked to a "heavy" chain by two disulphide bonds. beta-acrosin is thought to be multifunctional with roles in acrosomal exocytosis, as a receptor for zona pellucida proteins, and as a protease to facilitate penetration of spermatozoa into the egg. RESULTS: The crystal structures of both ram and boar beta-acrosins have been solved in complex with p-aminobenzamidine to 2.1 A and 2.9 A resolution, respectively. Both enzymes comprise a heavy chain with structural homology to trypsin, and a light chain covalently associated in a similar manner to blood coagulation enzymes. In crystals of boar beta-acrosin, the carboxyl terminus of the heavy chain is inserted into the active site of the neighboring molecule. In both enzyme structures, there are distinctive positively charged surface "patches" close to the active site, which associate with carbohydrate from adjacent molecules and also bind sulfate ions. CONCLUSIONS: From the three-dimensional structure of beta-acrosin, two separate effector sites are evident. First, proteolytic activity, believed to be important at various stages during fertilization, arises from the trypsin-like active site. Activity of this site may be autoregulated through intermolecular associations. Second, positively charged regions on the surface adjacent to the active site may act as receptors for binding zona pellucida glycoproteins. The spatial proximity of these two effector sites suggests there may be synergy between them.

Selected figure(s)

Figure 4.
Figure 4. Active Site of Boar b-Acrosin(a) The boar b-acrosin heavy chain carboxyl terminus inserts into the active site of a neighboring molecule. The figure shows the placement of the heavy chain carboxyl terminus (residues Pro-255, Pro-256, and Arg-257) and adjacent loop residues Asp-201, Arg-202, and Ala-203 within the active site of another molecule (shown as a molecular surface). The location of the catalytic site serine (Ser-195) is marked by the pink surface, the p-aminobenzamidine inhibitor is shown in green, and the specificity pockets are labeled according to the convention of [24].(b) Corresponding electron density (2|F[obs]| - |F[calc]| coefficients contoured at 1 s) for the active site region shown in part (a). Density for the residues inserted into the active site are shown, along with the density corresponding to the active site serine (Ser-195) and the p-aminobenzamidine inhibitor

The above figure is reprinted by permission from Cell Press: Structure (2000, 8, 1179-1188) copyright 2000.

Figure was selected by the author.