title: An artificially evolved albumin binding module facilitates chemical shift epitope mapping of GA domain interactions with phylogenetically diverse albumins.
abstract: Protein G-related albumin-binding (GA) modules occur on the surface of numerous Gram-positive bacterial pathogens and their presence may promote bacterial growth and virulence in mammalian hosts. We recently used phage display selection to evolve a GA domain, PSD-1 (phage selected domain-1), which tightly bound phylogenetically diverse albumins. With respect to PSD-1's broad albumin binding specificity, it remained unclear how the evolved binding epitope compared to those of naturally occurring GA domains and whether PSD-1's binding mode was the same for different albumins. We investigate these questions here using chemical shift perturbation measurements of PSD-1 with rabbit serum albumin (RSA) and human serum albumin (HSA) and put the results in the context of previous work on structure and dynamics of GA domains. Combined, these data provide insights into the requirements for broad binding specificity in GA-albumin interactions. Moreover, we note that using the phage-optimized PSD-1 protein significantly diminishes the effects of exchange broadening at the binding interface between GA modules and albumin, presumably through stabilization of a ligand-bound conformation. The employment of artificially evolved domains may be generally useful in NMR structural studies of other protein-protein complexes.
authors.affiliation: Center for Advanced Research in Biotechnology, University of Maryland Biotechnology Institute, Rockville, MD 20850, USA.
authors.forename: Yanan
authors.initials: Y
authors.lastname: He
authors.forename: Yihong
authors.initials: Y
authors.lastname: Chen
authors.forename: David A
authors.initials: DA
authors.lastname: Rozak
authors.forename: Philip N
authors.initials: PN
authors.lastname: Bryan
authors.forename: John
authors.initials: J
authors.lastname: Orban
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D011485:Protein Binding; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D011817:Rabbits; D017386:Sequence Homology, Amino Acid; D012709:Serum Albumin / Q000737:chemistry* / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; C029152:G-substrate; D009419:Nerve Tissue Proteins; D012709:Serum Albumin