A phage display system for studying the sequence determinants of protein folding.
We have developed a phage display system that provides a means to select variants of the IgG binding domain of peptostreptococcal protein L that fold from large combinatorial libraries. The premise underlying the selection scheme is that binding of protein L to IgG requires that the protein be properly folded. Using a combination of molecular biological and biophysical methods, we show that this assumption is valid. First, the phage selection procedure strongly selects against a point mutation in protein L that disrupts folding but is not in the IgG binding interface. Second, variants recovered from a library in which the first third of protein L was randomized are properly folded. The degree of sequence variation in the selected population is striking: the variants have as many as nine substitutions in the 14 residues that were mutagenized. The approach provides a selection for "foldedness" that is potentially applicable to any small binding protein.
Gu
H
H
Department of Biochemistry, University of Washington, Seattle 98195, USA.
Yi
Q
Q
Bray
S T
ST
Riddle
D S
DS
Shiau
A K
AK
Baker
D
D
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D017104:Bacteriophage M13 / Q000235:genetics*; D001483:Base Sequence; D002942:Circular Dichroism; D015723:Gene Library; D005822:Genetic Vectors / Q000235:genetics; D008958:Models, Molecular; D008969:Molecular Sequence Data; D016296:Mutagenesis; D010957:Plasmids / Q000235:genetics; D011489:Protein Denaturation; D017510:Protein Folding; D011994:Recombinant Proteins / Q000378:metabolism; D012641:Selection, Genetic; D013329:Structure-Activity Relationship
D001426:Bacterial Proteins; C055047:Ig L-binding protein, Peptostreptococcus; D011994:Recombinant Proteins