Conformational analysis of the leukocyte-specific EF-hand protein p65/L-plastin by X-ray scattering in solution.
p65/L-Plastin is a leukocyte-specific EF-hand protein which plays a vital role in organizing the actin cytoskeleton. Since its overall structural information has been largely unknown, we employed the X-ray scattering technique to elucidate the structure. Kratky plots of p65/L-plastin showed one peak, indicating that the protein takes compact globular conformations. The radii of gyration (Rg) of the monomer p65/L-plastin estimated from Guinier plots were 27.5 +/- 0.5 A and 28.6 A in the absence and presence of Ca(2+), respectively. The distance distribution function P(r) gave single peaks at 31.5-32.3 A and 33 A in the absence and presence of Ca(2+), respectively. These indicate that p65/L-plastin becomes somewhat larger in the presence of Ca(2+). The molecular shape of p65/L-plastin reconstructed from X-ray scattering data using the DAMMIN program has provided the first view of the overall structure of full-length plastin/fimbrin family proteins: a compact horseshoe-like shape with a small projection, which also exhibits Ca(2+) -induced conformational changes.
Shinomiya
Hiroto
H
Department of Immunology and Host Defenses, Graduate School of Medicine of Ehime University, Ehime, Japan. hiroto@m.ehime-u.ac.jp
Shinjo
Masaji
M
Fengzhi
Liu
L
Asano
Yoshihiro
Y
Kihara
Hiroshi
H
D020816:Amino Acid Motifs; D000818:Animals; D002118:Calcium / Q000737:chemistry; D008562:Membrane Glycoproteins; D051379:Mice; D008840:Microfilament Proteins; D010750:Phosphoproteins / Q000737:chemistry* / Q000235:genetics; D011487:Protein Conformation; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics; D012542:Scattering, Radiation; D012996:Solutions; D014965:X-Rays
D008562:Membrane Glycoproteins; D008840:Microfilament Proteins; D010750:Phosphoproteins; D011994:Recombinant Proteins; D012996:Solutions; C026742:plastin; D002118:Calcium