Functional assembly of a randomly cleaved protein.
The sequence of a 939-amino acid polypeptide that is a member of the aminoacyl-tRNA synthetase class of enzymes has been aligned with sequences of 15 related proteins. This alignment guided the design of 18 fragment pairs that were tested for internal sequence complementarity by reconstitution of enzyme activity. Reconstitution was achieved with fragments that divide the protein at both nonconserved and conserved sequences, including locations proximal to or within elements believed to form critical elements of secondary structure. Structure assembly is sufficiently flexible to accommodate fusion of short segments of unrelated sequences at fragment junctions. Complementary chain packing interactions and chain flexibility appear to be widely distributed throughout the sequence and are sufficient to reconstruct large three-dimensional structures from an array of disconnected pieces. The results may have implications for the evolution and assembly of large proteins.
Shiba
K
K
Department of Biology, Massachusetts Institute of Technology, Cambridge 02139.
Schimmel
P
P
D000595:Amino Acid Sequence; D000604:Amino Acyl-tRNA Synthetases / Q000737:chemistry*; D001426:Bacterial Proteins / Q000737:chemistry; D001665:Binding Sites; D005075:Biological Evolution; D003001:Cloning, Molecular; D005656:Fungal Proteins / Q000737:chemistry; D005816:Genetic Complementation Test; D007533:Isoleucine-tRNA Ligase / Q000737:chemistry*; D008969:Molecular Sequence Data; D015183:Restriction Mapping; D016415:Sequence Alignment; D013329:Structure-Activity Relationship
D001426:Bacterial Proteins; D005656:Fungal Proteins; D000604:Amino Acyl-tRNA Synthetases; D007533:Isoleucine-tRNA Ligase