Structure, specificity, and mode of interaction for bacterial albumin-binding modules.
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.
Johansson
Maria U
MU
Department of Biophysical Chemistry, Lund University, P.O. Box 124, SE-221 00 Lund, Sweden. maria.johansson@bpc.lu.se
Frick
Inga-Maria
IM
Nilsson
Hanna
H
Kraulis
Per J
PJ
Hober
Sophia
S
Jonasson
Per
P
Linhult
Martin
M
Nygren
Per-Ake
PA
Uhlén
Mathias
M
Björck
Lars
L
Drakenberg
Torbjörn
T
Forsén
Sture
S
Wikström
Mats
M
D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D001667:Binding, Competitive; D002942:Circular Dichroism; D004305:Dose-Response Relationship, Drug; D004351:Drug Resistance; D019143:Evolution, Molecular; D020128:Inhibitory Concentration 50; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010462:Peptostreptococcus / Q000378:metabolism*; D011485:Protein Binding; D011817:Rabbits; D017386:Sequence Homology, Amino Acid; D012709:Serum Albumin / Q000737:chemistry* / Q000378:metabolism; D013379:Substrate Specificity; D013696:Temperature
D012709:Serum Albumin