Download MendeleyA Trichomonas vaginalis C2-XYPPX-repeat protein with a structured C2 domain displaying dampened flexibility upon binding calcium.
Buchko, G.W., Liu, L., Battaile, K.P., Craig, J.K., Harmon, E.K., Van Voorhis, W.C., Myler, P.J., Lovell, S.(2025) Biochimie 241: 44-55
- PubMed: 41285221
- DOI: https://doi.org/10.1016/j.biochi.2025.11.011
- Primary Citation of Related Structures:
9BKW - PubMed Abstract:
C2 domains are ubiquitous membrane-binding modules of ∼130 residues in eukaryotes that are often associated with proteins involved in membrane trafficking and lipid modification. The genome of Trichomonas vaginalis, the most common, non-viral, sexually transmitted human pathogen, encodes eight genes that contain a N-terminal C2 module linked to a XYPPX-repeat domain of more than four XYPPX repeats (C2-XYPPX). While the function of the XYPPX-repeat domain remains unknown, its multiple association with C2 domains in T. vaginalis suggests it is important. The C2 domain from one of these C2-XYPPX-repeat proteins, Tv-C2-1, was structurally and physically characterized using X-ray crystallography and NMR spectroscopy. The crystal structure for Tv-C2-1 shows that this domain shares a fold common to all C2 domains, a compact Greek-key motif composed of eight anti-parallel β-strands in the type-2 topology. An NMR chemical shift perturbation study with Ca 2+ showed that Tv-C2-1 bound two Ca 2+ atoms primarily via two loops (loop-1 and loop-3) on the predicted calcium binding face of the protein with K d s of 58.0 ± 0.1 μM and 232 ± 6 μM. Estimations of the overall rotational correlation time, τ c , in the apo (11.1 ns) and Ca 2+ -bound (9.2 ns) state suggests the protein becomes more compact upon Ca 2+ binding, consistent with a decrease in dynamics in loop-3 and marginally in loop-1 suggested by amide 15 N heteronuclear steady-state { 1 H}- 15 N NOEs. Showing Tv-C2-1 binds calcium and adopts a compact Greek-key motif structure, two primary features of C2 domains, suggests understanding the function of the XYPPX-repeat domain may be warranted.
- Seattle Structural Genomics Center for Infectious Disease, Seattle, WA, USA; Earth and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA, 99354, USA; School of Molecular Biosciences, Washington State University, Pullman, WA, 99164, USA. Electronic address: garry.buchko@pnnl.gov.
Organizational Affiliation:
