Synthesis, screening, and sequencing of cysteine-rich one-bead one-compound peptide libraries.
Cysteine-rich peptides are valued as tags for biarsenical fluorophores and as environmentally important reagents for binding toxic heavy metals. Due to the inherent difficulties created by cysteine, the power of one-bead one-compound (OBOC) libraries has never been applied to the discovery of short cysteine-rich peptides. We have developed the first method for the synthesis, screening, and sequencing of cysteine-rich OBOC peptide libraries. First, we synthesized a heavily biased cysteine-rich OBOC library, incorporating 50% cysteine at each position (Ac-X8-KM-TentaGel). Then, we developed conditions for cysteine alkylation, cyanogen bromide cleavage, and direct MS/MS sequencing of that library at the single bead level. The sequencing efficiency of this library was comparable to a traditional cysteine-free library. To validate screening of cysteine-rich OBOC libraries, we reacted a library with the biarsenical FlAsH and identified beads bearing the known biarsenical-binding motif (CCXXCC). These results enable OBOC libraries to be used in high-throughput discovery of cysteine-rich peptides for protein tagging, environmental remediation of metal contaminants, or cysteine-rich pharmaceuticals.
Juskowiak
Gary L
GL
Department of Chemistry, 1102 Natural Sciences 2, University of California, Irvine, California 92697-2025, USA.
McGee
Christopher J
CJ
Greaves
John
J
Van Vranken
David L
DL
D000478:Alkylation; D000595:Amino Acid Sequence; D000596:Amino Acids / Q000737:chemistry; D002853:Chromatography, Liquid; D020650:Combinatorial Chemistry Techniques / Q000379:methods*; D003488:Cyanogen Bromide / Q000737:chemistry; D003545:Cysteine / Q000031:analogs & derivatives / Q000138:chemical synthesis*; D013058:Mass Spectrometry; D008863:Microspheres; D019151:Peptide Library; D010455:Peptides / Q000737:chemistry*; D012117:Resins, Synthetic / Q000737:chemistry
D000596:Amino Acids; D019151:Peptide Library; D010455:Peptides; D012117:Resins, Synthetic; D003545:Cysteine; D003488:Cyanogen Bromide