The cystic fibrosis transmembrane conductance regulator. Effects of the most common cystic fibrosis-causing mutation on the secondary structure and stability of a synthetic peptide.
Deletion of phenylalanine 508 (delta Phe-508) in the cystic fibrosis transmembrane conductance regulator (CFTR) protein causes approximately 70% of all cases of cystic fibrosis. This residue lies in a region of the protein that we have synthesized chemically and shown to bind adenine nucleotides (Thomas, P. J., Shenbagamurthi, P., Ysern, X., and Pedersen, P. L. (1991) Science 251, 555-557). A peptide lacking this critical residue, but otherwise corresponding to this crucial part of the protein, now also has been chemically synthesized and purified. This mutant peptide (P-66) exhibits a significant loss of beta-sheet structure as compared with the wild type peptide (P-67). Furthermore, urea denaturation of peptide structure reveals that P-66 is less stable than P-67. Although under non-denaturing conditions both peptides bind adenine nucleotides with high affinity, the loss of structural stability is reflected in the binding function of the peptides. Thus, P-67, in contrast to P-66, retains a significant capacity for nucleotide binding in 4 M urea. These results suggest a model for impaired delta Phe-508 CFTR function.
Thomas
P J
PJ
Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205.
Shenbagamurthi
P
P
Sondek
J
J
Hullihen
J M
JM
Pedersen
P L
PL
D000255:Adenosine Triphosphate / Q000378:metabolism; D000595:Amino Acid Sequence; D001665:Binding Sites; D002872:Chromosome Deletion; D002942:Circular Dichroism; D003550:Cystic Fibrosis / Q000235:genetics*; D019005:Cystic Fibrosis Transmembrane Conductance Regulator; D006801:Humans; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009154:Mutation; D010455:Peptides / Q000138:chemical synthesis / Q000737:chemistry / Q000378:metabolism; D011487:Protein Conformation
C505032:CFTR protein, human; D008565:Membrane Proteins; D010455:Peptides; D019005:Cystic Fibrosis Transmembrane Conductance Regulator; D000255:Adenosine Triphosphate