PDBsum entry 1ah2

Serine protease

PDB id: 1ah2

Contents

Protein chain

269 a.a. *

* Residue conservation analysis

PDB id:

1ah2

Name:

Serine protease

Title:

Serine protease pb92 from bacillus alcalophilus, nmr, 18 structures

Structure:

Serine protease pb92. Chain: a. Engineered: yes. Other_details: inhibited by dfp

Source:

Bacillus alcalophilus. Organism_taxid: 1445. Strain: pb92. Expressed in: bacillus subtilis. Expression_system_taxid: 1423

NMR struc:

18 models

Authors:

R.Boelens,D.Schipper,J.R.Martin,Y.Karimi-Nejad,F.Mulder,J.V.D.Zwan, M.Mariani

Key ref:

J.R.Martin et al. (1997). The solution structure of serine protease PB92 from Bacillus alcalophilus presents a rigid fold with a flexible substrate-binding site. Structure, 5, 521-532. PubMed id: 9115441 DOI: 10.1016/S0969-2126(97)00208-6

Date:

11-Apr-97 Release date: 15-Apr-98

Protein chain

P27693  (ELYA_ALKAL) -  Alkaline protease from Alkalihalobacillus alcalophilus

Seq: 380 a.a.

Struc: 269 a.a.

Enzyme reactions

• Enzyme class: E.C.3.4.21.- - ?????

DOI no: 10.1016/S0969-2126(97)00208-6

Structure 5:521-532 (1997)

PubMed id: 9115441

The solution structure of serine protease PB92 from Bacillus alcalophilus presents a rigid fold with a flexible substrate-binding site.

J.R.Martin, F.A.Mulder, Y.Karimi-Nejad, J.van der Zwan, M.Mariani, D.Schipper, R.Boelens.

ABSTRACT

BACKGROUND: Research on high-alkaline proteases, such as serine protease PB92, has been largely inspired by their industrial application as protein-degrading components of washing powders. Serine protease PB92 is a member of the subtilase family of enzymes, which has been extensively studied. These studies have included exhaustive protein engineering investigations and X-ray crystallography, in order to provide insight into the mechanism and specificity of enzyme catalysis. Distortions have been observed in the substrate-binding region of subtilisin crystal structures, due to crystal contacts. In addition, the structural variability in the substrate-binding region of subtilisins is often attributed to flexibility. It was hoped that the solution structure of this enzyme would provide further details about the conformation of this key region and give new insights into the functional properties of these enzymes. RESULTS: The three-dimensional solution structure of the 269-residue (27 kDa) serine protease PB92 has been determined using distance and dihedral angle constraints derived from triple-resonance NMR data. The solution structure is represented by a family of 18 conformers which overlay onto the average structure with backbone and all-heavy-atom root mean square deviations (for the main body of the molecule) of 0.88 and 1.21 A, respectively. The family of structures contains a number of regions of relatively high conformational heterogeneity, including various segments that are involved in the formation of the substrate-binding site. The presence of flexibility within these segments has been established from NMR relaxation parameters and measurements of amide proton exchange rates. CONCLUSIONS: The solution structure of the serine protease PB92 presents a well defined global fold which is rigid with the exception of a restricted number of sites. Among the limited number of residues involved in significant internal mobility are those of two pockets, termed S1 and S4, within the substrate-binding site. The presence of flexibility within the binding site supports the proposed induced fit mechanism of substrate binding.

Selected figure(s)

Figure 4.
Figure 4. Overlay of all Ca atoms of the NMR ensemble (shown in dark blue) onto the Ca atoms of the crystal structure [16], drawn in pale blue.

The above figure is reprinted by permission from Cell Press: Structure (1997, 5, 521-532) copyright 1997.

Figure was selected by an automated process.