Model of fibronectin tertiary structure based on studies of interactions between fragments.
Human plasma fibronectin aggregates in solution and is thought to form fibrils on cell surfaces, perhaps by self-associating and by interacting with other components such as proteoglycans. We have localized the self-association domains by testing the ability of various fragments of fibronectin to interact with each other. Complexation between fluorescamine-labeled fragments and unlabeled fragments or whole molecules was assessed by gel filtration high-performance liquid chromatography. The fragments studied included nonoverlapping fragments that are situated on the fibronectin polypeptide chain in the following order, beginning from the amino terminus: the 29-, 50-, 120-, 35-, and 25-kDa fragments, as well as multiple-domain fragments of 72 kDa containing the 29- and 50-kDa segments, a fragment of 150 kDa containing the 120- and 35-kDa segment, a fragment of 190 kDa containing the 120- and 35-kDa segments, a fragment of 190 kDa containing the 50-, 150-, and 25-kDa segments, and a 45-kDa fragment containing the 35-kDa segment. The amino-terminal 29-kDa fragment bound to the carboxyl-terminal heparin-binding (Hep II) 35-kDa fragment as well as the 150- and 190-kDa fragments that contain the 35-kDa segment. On the other hand, carboxyl-terminal 35- and 45-kDa Hep II containing fragments bound to each other as well as to amino-terminal 29- and 72-kDa fragments and to the 190-kDa fragment. Further, the 25-kDa carboxyl-terminal fibrin-binding fragment bound the 190-kDa fragment, the only fragment containing the 25-kDa segment.(ABSTRACT TRUNCATED AT 250 WORDS)
D000595:Amino Acid Sequence; D002402:Cathepsin D; D005353:Fibronectins / Q000378:metabolism*; D006801:Humans; D046911:Macromolecular Substances; D008958:Models, Molecular; D008970:Molecular Weight; D010446:Peptide Fragments / Q000378:metabolism; D013438:Sulfhydryl Compounds / Q000032:analysis
D005353:Fibronectins; D046911:Macromolecular Substances; D010446:Peptide Fragments; D013438:Sulfhydryl Compounds; D002402:Cathepsin D