Cysteine residue periodicity is a conserved structural feature of variable surface proteins from Paramecium tetraurelia.
The DNA sequences of the entire coding regions of the A and C type variable surface protein genes from Paramecium tetraurelia, stock 51 have been determined. The 8151 nucleotide open reading frame of the A gene contains several tandem repeats of 210 nucleotides within the central portion of the molecule as well as a periodic structure defined by cysteine residues. The 6699 nucleotide open reading frame of the C gene does not contain any identifiable tandem repeats or internal similarity but maintains a periodicity based on the cysteine residue spacing. The deduced amino acid sequences encoded by the two genes are most similar within the 600 amino-terminal and 600 carboxyl-terminal amino acid residues, the central portions show only limited sequence similarity. We conclude that internal repeats are not a conserved feature of variable surface proteins in Paramecium and discuss the possible importance of the regular pattern of cysteine residues.
Nielsen
E
E
Department of Biochemistry, Purdue University, West Lafayette, IN 47907.
You
Y
Y
Forney
J
J
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003545:Cysteine; D004247:DNA / Q000235:genetics*; D005796:Genes; D008565:Membrane Proteins / Q000235:genetics*; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D010247:Paramecium / Q000235:genetics*; D015800:Protozoan Proteins / Q000235:genetics*; D012689:Sequence Homology, Nucleic Acid
D008565:Membrane Proteins; D015800:Protozoan Proteins; D004247:DNA; D003545:Cysteine