PDBsum entry 1gjs

Immunoglobulin-binding protein

PDB id: 1gjs

Contents

Protein chain

65 a.a. *

* Residue conservation analysis

PDB id:

1gjs

Name:

Immunoglobulin-binding protein

Title:

Solution structure of the albumin binding domain of streptococcal protein g

Structure:

Immunoglobulin g binding protein g. Chain: a. Fragment: albumin-binding domain residues 254-299. Synonym: abd, albumin-binding domain of protein g, igg binding protein g. Engineered: yes

Source:

Streptococcus sp.. Group g streptococci. Organism_taxid: 1306. Expressed in: escherichia coli. Expression_system_taxid: 562

NMR struc:

30 models

Authors:

M.U.Johansson,I.M.Frick,H.Nilsson,P.J.Kraulis,S.Hober,P.Jonasson, A.P.Nygren,M.Uhlen,L.Bjorck,T.Drakenberg,S.Forsen,M.Wikstrom

Key ref:

M.U.Johansson et al. (2002). Structure, specificity, and mode of interaction for bacterial albumin-binding modules. J Biol Chem, 277, 8114-8120. PubMed id: 11751858 DOI: 10.1074/jbc.M109943200

Date:

02-Aug-01 Release date: 09-Aug-01

Protein chain

P19909  (SPG2_STRSG) -  Immunoglobulin G-binding protein G from Streptococcus sp. group G

Seq: 593 a.a.

Struc: 65 a.a.*

* PDB and UniProt seqs differ at 18 residue positions (black crosses)

DOI no: 10.1074/jbc.M109943200

J Biol Chem 277:8114-8120 (2002)

PubMed id: 11751858

Structure, specificity, and mode of interaction for bacterial albumin-binding modules.

M.U.Johansson, I.M.Frick, H.Nilsson, P.J.Kraulis, S.Hober, P.Jonasson, M.Linhult, P.A.Nygren, M.Uhlén, L.Björck, T.Drakenberg, S.Forsén, M.Wikström.

ABSTRACT

We have determined the solution structure of an albumin binding domain of protein G, a surface protein of group C and G streptococci. We find that it folds into a left handed three-helix bundle similar to the albumin binding domain of protein PAB from Peptostreptococcus magnus. The two domains share 59% sequence identity, are thermally very stable, and bind to the same site on human serum albumin. The albumin binding site, the first determined for this structural motif known as the GA module, comprises residues spanning the first loop to the beginning of the third helix and includes the most conserved region of GA modules. The two GA modules have different affinities for albumin from different species, and their albumin binding patterns correspond directly to the host specificity of C/G streptococci and P. magnus, respectively. These studies of the evolution, structure, and binding properties of the GA module emphasize the power of bacterial adaptation and underline ecological and medical problems connected with the use of antibiotics.

Selected figure(s)

Figure 2.
Fig. 2. Structural features of GA modules. Panel A, stereo representation of 30 G148-GA3 NMR solution structures superimposed onto their unminimized average coordinates by minimizing the r.m.s. deviations for the backbone atoms of helices. Panel B, ribbon representation of the structure closest to the mean of the 30 structures representing G148-GA3. Panel C, ribbon representation of the structure closest to the mean of the 20 structures (the atomic coordinates are available in the Research Collaboratory for Structural Bioinformatics Protein Data Bank under PDB 1GAB (13)). The whole protein fragment of ALB8-GA (53 residues) is shown, and the corresponding residues of G148-GA3 are shown in panel B, although not all residues belong to the intact protein G sequence. Panel D, tube representation of ALB8-GA (light gray) and G148-GA3 (dark gray) with backbone atoms of helical regions superimposed. Residue Thr-18 in ALB8-GA is indicated with an arrow, and at the corresponding position in G148-GA3 there is a deletion. Structures (all oriented with their N terminus upward) in panels A-D were visualized using MOLMOL (40). Panel E, graphical DDM comparing the two GA modules in this study. The average distance differences between C^ and C^ in the 30 conformers of G148-GA3 and the 20 structures of ALB8-GA (PDB 1GAB (13) were calculated to generate the DDM (29). Only residues belonging to the defined GA module sequence were analyzed. Residue Thr-18 in ALB8-GA was excluded because there is a deletion at the corresponding position in the G148-GA3 sequence, and these locations are marked by arrows. The lower right half of the matrix shows the average distance differences for all residue pairs; the upper left part shows only the average distance differences that are larger than 2 S.D. The distance differences are coded using a gradient from white to black with gray representing interatomic distances that are the same in both ensembles. Interatomic distances that become larger in G148-GA3 tend toward white, whereas distances that become smaller tend toward black.

Figure 3.
Fig. 3. Albumin binding site of ALB8-GA and G148-GA3. Panel A, chemical shift perturbations upon addition of 0.6 eq of rabbit serum albumin to ALB8-GA at 37 °C. Panel B, same as panel A but for G148-GA3. The chemical shift change was calculated from the chemical shift of the backbone 15N and 1H resonances using the following formula: = (( (1H))2 + (0.2 (15N))2)1/2 and is indicated with a filled bar at the corresponding residue. Each residue for which the cross-peak is broadened beyond detection upon the addition of albumin is indicated by a green bar at the value of 0.14 ppm (corresponding to the maximum chemical shift change of residues with nonbroadened cross-peaks). Residues that were too weak to give any reliable information, overlapped, or were not detected at all are indicated with outlined circles at a value of 0 ppm. The helices are indicated by boxes at the top. Panel C, overlay of a region of 15N-1H HSQC spectra of 2 mM ALB8-GA at 47 °C in the absence (blue) and in the presence (red) of 1 eq of rabbit serum albumin with the residue numbers indicated. For details, see "Results and Discussion." Panels D and E, contact surfaces displaying the effects of albumin binding shown in two different views differing by a 180° rotation along the y axis. The orientation of the views to the left is the same as in the ribbon representations in Fig. 2, panels C and B, respectively. The 18 (ALB8-GA, panel D) and 20 (G148-GA3, panel E) significantly perturbed residues are indicated in red. Residues that were too weak to give any reliable information, overlapped, or were not detected at all are shown in magenta. The remaining residues are colored blue. To clarify the presentation, only residues belonging to the defined GA module sequence are shown. The contact surfaces in panels D and E were prepared using MOLMOL (40).

The above figures are reprinted by permission from the ASBMB: J Biol Chem (2002, 277, 8114-8120) copyright 2002.

Figures were selected by an automated process.