Involvement of the N-terminal part of cyclophilin B in the interaction with specific Jurkat T-cell binding sites.
Cyclophilin B (CyPB) is secreted in biological fluids such as blood or milk and binds to a specific receptor present on the human lymphoblastic cell line Jurkat and on human peripheral blood lymphocytes. This study was intended to specify the areas of CyPB that are involved in the interaction with the receptor. A synthetic peptide corresponding to the first 24 N-terminal amino acid residues of CyPB was shown to specifically recognize the receptor. Moreover, modification of Arg18 of CyPB by p-hydroxyphenlglyoxal led to a dramatic loss of affinity for the receptor. However, when this residue was replaced by an alanine residue using site-directed mutagenesis, no modification of the binding properties was found, suggesting that Arg18 is not directly involved but is sufficiently close to the interaction site to interfere with the binding when modified. Competitive binding experiments using a chimaeric protein made up of the 24 N-terminal amino acid residues of CyPB fused to the cyclophilin A core sequence confirmed the involvement of this region of CyPB in receptor binding.
Mariller
C
C
Laboratoire de Chimie Biologique, Université des Sciences et Technologies de Lille, Villeneuve d'Ascq, France.
Haendler
B
B
Allain
F
F
Denys
A
A
Spik
G
G
D000591:Amino Acid Isomerases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D000595:Amino Acid Sequence; D001665:Binding Sites; D001667:Binding, Competitive; D002352:Carrier Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D000072622:Cyclophilin C; D021983:Cyclophilins; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006801:Humans; D007527:Isoenzymes / Q000378:metabolism; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000378:metabolism*; D019696:Peptidylprolyl Isomerase; D010658:Phenylglyoxal / Q000031:analogs & derivatives / Q000494:pharmacology; D018000:Receptors, Peptide / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D013056:Spectrophotometry, Ultraviolet; D013601:T-Lymphocytes / Q000378:metabolism*
D002352:Carrier Proteins; D004791:Enzyme Inhibitors; D007527:Isoenzymes; D010446:Peptide Fragments; D018000:Receptors, Peptide; D011993:Recombinant Fusion Proteins; C100811:cyclophilin B receptor; C081786:cyclophilin B; C028465:4-hydroxyphenylglyoxal; D000591:Amino Acid Isomerases; D021983:Cyclophilins; D000072622:Cyclophilin C; D019696:Peptidylprolyl Isomerase; D010658:Phenylglyoxal