Disulfide bonds are neither required, present, nor compatible with full activity of human recombinant acidic fibroblast growth factor.
Human acidic fibroblast growth factor (aFGF) is a potent broad-spectrum mitogen that contains three Cys residues within its monomeric structure. We have found that site-directed mutants in which any one of these Cys residues is converted to serine remain highly active, although variably dependent on heparin, so none of the three possible intramolecular disulfide bonds that can be formed are required for mitogenic activity. Furthermore, a dispensable disulfide bond that might stabilize the active conformation is not present since all three Cys residues are accessible to chemical modification in recombinant as well as brain-derived aFGFs. Finally, formation of a disulfide bond between the two Cys residues conserved among all seven known members of the FGF family results in a virtually inactive product that can subsequently be reactivated by reduction. Thus, despite the extracellular function of aFGF, its Cys residues do not form intramolecular disulfide bonds in the active conformation.
Linemeyer
D L
DL
Department of Biochemistry, Merck Institute for Therapeutic Research, Merck Sharp and Dohme Research Laboratories, Rahway, New Jersey 07065.
Menke
J G
JG
Kelly
L J
LJ
DiSalvo
J
J
Soderman
D
D
Schaeffer
M T
MT
Ortega
S
S
Gimenez-Gallego
G
G
Thomas
K A
KA
D000818:Animals; D001483:Base Sequence; D002455:Cell Division / Q000187:drug effects; D002460:Cell Line; D003545:Cysteine; D004261:DNA Replication / Q000187:drug effects*; D004220:Disulfides / Q000032:analysis; D016220:Fibroblast Growth Factor 1 / Q000235:genetics / Q000302:isolation & purification / Q000494:pharmacology*; D006801:Humans; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D015345:Oligonucleotide Probes; D011994:Recombinant Proteins / Q000302:isolation & purification / Q000494:pharmacology; D013329:Structure-Activity Relationship
D004220:Disulfides; D015345:Oligonucleotide Probes; D011994:Recombinant Proteins; D016220:Fibroblast Growth Factor 1; D003545:Cysteine