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An artificially evolved albumin binding module facilitates chemical shift epitope mapping of GA domain interactions with phylogenetically diverse albumins
Author(s) -
He Yanan,
Chen Yihong,
Rozak David A.,
Bryan Philip N.,
Orban John
Publication year - 2007
Publication title -
protein science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.353
H-Index - 175
eISSN - 1469-896X
pISSN - 0961-8368
DOI - 10.1110/ps.072799507
Subject(s) - epitope , plasma protein binding , albumin , context (archaeology) , epitope mapping , human serum albumin , biology , serum albumin , biophysics , protein domain , biochemistry , binding domain , protein structure , chemistry , binding site , computational biology , genetics , gene , antigen , paleontology
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.