Rab-subfamily-specific regions of Ypt7p are structurally different from other RabGTPases.
Constantinescu, A.T., Rak, A., Alexandrov, K., Esters, H., Goody, R.S., Scheidig, A.J.(2002) Structure 10: 569-579
- PubMed: 11937061 
- DOI: https://doi.org/10.1016/s0969-2126(02)00737-2
- Primary Citation of Related Structures:  
1KY2, 1KY3 - PubMed Abstract: 
The GTPase Ypt7p from S. cerevisiae is involved in late endosome-to-vacuole transport and homotypic vacuole fusion. We present crystal structures of the GDP- and GppNHp-bound conformation of Ypt7p solved at 1.35 and 1.6 A resolution, respectively. Despite the similarity of the overall structure to other Ypt/Rab proteins, Ypt7p displays small but significant differences. The Ypt7p-specific residues Tyr33 and Tyr37 cause a difference in the main chain trace of the RabSF2 region and form a characteristic surface epitope. Ypt7p*GppNHp does not display the helix alpha2, characteristic of the Ras-superfamily, but instead possess an extended loop L4/L5. Due to insertions in loops L3 and L7, the neighboring RabSF1 and RabSF4 regions are different in their conformations to those of other Ypt/Rab proteins.
Organizational Affiliation: 
Abteilung für Physikalische Biochemie, Max-Planck Institut für Molekulare Physiologie, Otto-Hahn Strasse 11, 44227 Dortmund, Germany.