PDBsum entry 2g8c

Lipid binding protein

PDB id: 2g8c

Contents

Protein chain

246 a.a. *

Ligands

IMD

PG4 ×2

Waters ×403

* Residue conservation analysis

PDB id:

2g8c

Name:

Lipid binding protein

Title:

Atomic-resolution crystal structure of borrelia burgdorferi ospa via surface entropy reduction

Structure:

Outer surface protein a. Chain: o. Engineered: yes. Mutation: yes

Source:

Borrelia burgdorferi. Lyme disease spirochete. Organism_taxid: 139. Expressed in: escherichia coli bl21(de3). Expression_system_taxid: 469008.

Resolution:

1.15Å R-factor: 0.155 R-free: 0.180

Authors:

K.Makabe,V.Tereshko,S.Koide

Key ref:

K.Makabe et al. (2006). Atomic-resolution crystal structure of Borrelia burgdorferi outer surface protein A via surface engineering. Protein Sci, 15, 1907-1914. PubMed id: 16823038 DOI: 10.1110/ps.062246706

Date:

02-Mar-06 Release date: 08-Aug-06

Protein chain

P0CL66  (OSPA_BORBU) -  Outer surface protein A from Borreliella burgdorferi (strain ATCC 35210 / DSM 4680 / CIP 102532 / B31)

Seq: 273 a.a.

Struc: 246 a.a.*

* PDB and UniProt seqs differ at 13 residue positions (black crosses)

DOI no: 10.1110/ps.062246706

Protein Sci 15:1907-1914 (2006)

PubMed id: 16823038

Atomic-resolution crystal structure of Borrelia burgdorferi outer surface protein A via surface engineering.

K.Makabe, V.Tereshko, G.Gawlak, S.Yan, S.Koide.

ABSTRACT

Outer surface protein A (OspA) from Borrelia burgdorferi has an unusual dumbbell-shaped structure in which two globular domains are connected with a "single-layer" beta-sheet (SLB). The protein is highly soluble, and it has been recalcitrant to crystallization. Only OspA complexes with Fab fragments have been successfully crystallized. OspA contains a large number of Lys and Glu residues, and these "high entropy" residues may disfavor crystal packing because some of them would need to be immobilized in forming a crystal lattice. We rationally designed a total of 13 surface mutations in which Lys and Glu residues were replaced with Ala or Ser. We successfully crystallized the mutant OspA without a bound Fab fragment and extended structure analysis to a 1.15 Angstroms resolution. The new high-resolution structure revealed a unique backbone hydration pattern of the SLB segment in which water molecules fill the "weak spots" on both faces of the antiparallel beta-sheet. These well-defined water molecules provide additional structural links between adjacent beta-strands, and thus they may be important for maintaining the rigidity of the SLB that inherently lacks tight packing afforded by a hydrophobic core. The structure also revealed new information on the side-chain dynamics and on a solvent-accessible cavity in the core of the C-terminal globular domain. This work demonstrates the utility of extensive surface mutation in crystallizing recalcitrant proteins and dramatically improving the resolution of crystal structures, and provides new insights into the stabilization mechanism of OspA.

Selected figure(s)

Figure 1.
Figure 1. (A) Superposition of the OspA structure in the 184.1 Fab complex (1OSP; blue) and that of OspAsm1 (red). Only the

The above figure is reprinted by permission from the Protein Society: Protein Sci (2006, 15, 1907-1914) copyright 2006.

Figure was selected by the author.