A proposed signaling motif for nuclear import in mRNA processing via the formation of arginine claw
- Howard Hughes Medical Institute, Center for Theoretical Biological Physics, Department of Chemistry and Biochemistry, Department of Pharmacology, University of California at San Diego, La Jolla, CA 92093-0365
-
Edited by Robert M. Stroud, University of California, San Francisco, CA, and approved July 26, 2007 (received for review April 5, 2007)
-
Fig. 1.A cartoon view of the sequence of ASF/SF2 with the RS domain shown in detail.
-
Fig. 2.The structure of the unphosphorylated (RS)8. (a) Two views of the helical structures formed. (b) The secondary structures are coded by colors for a time series of the simulation. The x axis is time, and the y axis is the residue index. For each point (x, y), a blue color indicates a helical structure is present for the residue y at time x, and red or gray indicates a strand or disordered secondary structure, respectively. Only the last one-fifth of the entire simulation is shown.
-
Fig. 3.The structure of the phosphorylated (RpS)8. (a) The “rod” structure formed by the phosphorylated (RpS)8. (b) The time series of the structure color-coded at the residue resolution level. The color code is the same as in Fig. 2: blue, helical; gray, disordered; red, strand. Only the last one-fifth of the entire simulation is shown.
-
Fig. 4.The time series of the structures color-coded at the residue resolution level are shown for several peptides, from a totally unphosphorylated form to partial and fully phosphorylated forms. The color code is the same as in Figs. 2 and 3: blue, helical; gray, disordered; red, strand. Only the last one-fifth of the entire simulation is shown.
-
Fig. 5.An arginine claw structure in which six arginines form contacts with a centered phosphoserine. In this particular claw, the center serine is the third serine residue.
-
Fig. 6.A zoomed-in view of the claw shows the hydrogen bonds formed between the phosphate group of the serine residue and the guanidinium moieties of the arginine residues that are stabilizing the claw structure.
Footnotes
- *To whom correspondence may be addressed at: Department of Chemistry and Biochemistry, University of California at San Diego, 9500 Gilman Drive, MC 0365, La Jolla, CA 92093-0365. E-mail: dhamelbe{at}mccammon.ucsd.edu
- © 2007 by The National Academy of Sciences of the USA
