FIGURE 1.

Chlamydomonas IFT A protein analysis. Sucrose density gradient-purified IFT A proteins were separated by electrophoresis with isolated tryptic peptides analyzed by Edman degradation as described under “Experimental Procedures.” IFT43 was excised from an SDS-PAGE gel of immunopurified IFT A (see supplemental Fig. S1) prior to trypsinization and MALDI-TOF mass spectroscopy. Three peptide masses resulting from the IFT43 analysis, 2122.9794, 1874.9612, and 2003.0562 Da, matched predicted masses of three peptide sequences, HVASTNFAPSGDDEPAPAPSR⁸⁶, GGAPPSRPPPAEILGEDSK¹¹⁸, and GGAPPSRPPPAEILGEDSKK¹¹⁹, respectively, that came from a single ORF in the Chlamydomonas genome. The third IFT43 peptide resulted from an incomplete cleavage at Lys¹¹⁹. WD, WD repeat domain; IR, intervening region; WAA, degenerate TPR-like repeats; CXXC, Cys-Xaa-Xaa-Cys repeat domain; TPR, tetratricopeptide repeats; TPR_V, TPR domain present in vertebrate THM1/IFT139; HT, half of a tetratricopeptide repeat; P, proline-rich domain.