title: Structure, specificity, and mode of interaction for bacterial albumin-binding modules.
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.
authors.affiliation: Department of Biophysical Chemistry, Lund University, P.O. Box 124, SE-221 00 Lund, Sweden. maria.johansson@bpc.lu.se
authors.forename: Maria U
authors.initials: MU
authors.lastname: Johansson
authors.forename: Inga-Maria
authors.initials: IM
authors.lastname: Frick
authors.forename: Hanna
authors.initials: H
authors.lastname: Nilsson
authors.forename: Per J
authors.initials: PJ
authors.lastname: Kraulis
authors.forename: Sophia
authors.initials: S
authors.lastname: Hober
authors.forename: Per
authors.initials: P
authors.lastname: Jonasson
authors.forename: Martin
authors.initials: M
authors.lastname: Linhult
authors.forename: Per-Ake
authors.initials: PA
authors.lastname: Nygren
authors.forename: Mathias
authors.initials: M
authors.lastname: Uhlén
authors.forename: Lars
authors.initials: L
authors.lastname: Björck
authors.forename: Torbjörn
authors.initials: T
authors.lastname: Drakenberg
authors.forename: Sture
authors.initials: S
authors.lastname: Forsén
authors.forename: Mats
authors.initials: M
authors.lastname: Wikström
mesh_terms: 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
chemical_list: D012709:Serum Albumin