Conformational and biochemical analysis of the cyclic peptides which modulate serine protease activity.
Prostate-specific antigen (PSA), a member of the kallikrein sub-group of the trypsin serine protease family, is a widely used marker for prostate cancer. Several sequences with specific binding to PSA have been identified by using phage display peptide libraries. The GST-fusion proteins of the characterized sequences have been shown to increase the enzyme activity of PSA to a synthetic substrate. The corresponding three cyclic synthetic analogues CVFTSNYAFC (A-1), CVFAHNYNYLVC (B-2) and CVAYCIEHHCWTC (C-4) have similar PSA promoting activity. Despite differences in the amino acid sequences, all three peptides bind to the same region of PSA. The conformation of the peptides was investigated by proton NMR spectroscopy. In addition, alanine replacement was used to characterize the prerequisites for binding. It is proposed that interactions with PSA are based on the aromatic and hydrophobic features of the amino acid side chains. Furthermore, it is suggested that peptides form beta-turn structures forced by cysteine bridges directing important aromatic side chains to the same side of the turn-structure.
Pakkala
Miikka
M
Department of Chemistry, University of Kuopio, Finland.
Jylhäsalmi
Anu
A
Wu
Ping
P
Leinonen
Jari
J
Stenman
Ulf-Håkan
UH
Santa
Harri
H
Vepsäläinen
Jouko
J
Peräkylä
Mikael
M
Närvänen
Ale
A
D000595:Amino Acid Sequence; D007610:Kallikreins / Q000037:antagonists & inhibitors / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010456:Peptides, Cyclic / Q000737:chemistry* / Q000378:metabolism / Q000494:pharmacology*; D017430:Prostate-Specific Antigen / Q000037:antagonists & inhibitors / Q000378:metabolism*; D011485:Protein Binding / Q000187:drug effects; D011487:Protein Conformation; D013696:Temperature
D010456:Peptides, Cyclic; D007610:Kallikreins; D017430:Prostate-Specific Antigen