Protein Science Attend a BioResearch Product Faire
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

Published online before print May 9, 2005, 10.1110/ps.041285605
Protein Science (2005), 14:1396-1409. Published by Cold Spring Harbor Laboratory Press. Copyright © 2005 The Protein Society
This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow All Versions of this Article:
ps.041285605v1
14/6/1396    most recent
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Otzen, D. E.
Right arrow Articles by Jensen, P. H.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Otzen, D. E.
Right arrow Articles by Jensen, P. H.
Social Bookmarking
Add to CiteULike   Add to Connotea   Add to Del.icio.us   Add to Digg   Add to Reddit   Add to Technorati  
What's this?

p25{alpha} is flexible but natively folded and binds tubulin with oligomeric stoichiometry

Daniel E. Otzen1, Ditte M.S. Lundvig2, Reinhard Wimmer1, Lotte H. Nielsen2, Jakob R. Pedersen1 and Poul H. Jensen2

1 Department of Life Sciences, Aalborg University, DK-9000 Aalborg, Denmark
2 Institute of Medical Biochemistry, Aarhus University, DK-8000 Aarhus, Denmark

(RECEIVED December 10, 2004; FINAL REVISION March 2, 2005; ACCEPTED March 9, 2005)

p25{alpha} is a 219-residue proteinwhich stimulates aberrant tubulin polymerization and is implicated in a variety of other functions. The protein has unusual secondary structure involving significant amounts of random coil, and binding to microtubules is accompanied by a large structural change, suggesting a high degree of plasticity. p25{alpha} has been proposed to be natively unfolded, so that folding is coupled to interaction with its physiological partners. Here we show that recombinant human p25{alpha} is folded under physiological conditions, since it has a well structured and solvent-sequestered aromatic environment and considerable chemical shift dispersion of amide and aliphatic protons. With increasing urea concentrations, p25{alpha} undergoes clear spectral changes suggesting significant loss of structure. p25{alpha} unfolds cooperatively in urea according to a simple two-state transition with a stability in water of ~5 kcal/mol. The protein behaves as a monomer and refolds with a transient on-pathway folding intermediate. However, high sensitivity to proteolytic attack and abnormal gel filtration migration behavior suggests a relatively extended structure, possibly organized in distinct domains. A deletion mutant of p25{alpha} lacking residues 3–43 also unfolds cooperatively and with similar stability, suggesting that the N-terminal region is largely unstructured. Both proteins undergo significant loss of structure when bound to monomeric tubulin. The stoichiometry of binding is estimated to be 3–4 molecules of tubulin per p25{alpha} and is not significantly affected by the deletion of residues 3–43. In conclusion, we dismiss the proposal that p25{alpha} is natively unfolded, although the protein is relatively flexible. This flexibility may be linked to its tubulin-binding properties.

Keywords: natively unfolded protein; stability; folding kinetics; tubulin; flexibility; binding stoichiometry

Abbreviations: ANS, 8-anilino-1-naphthalene-sulfonic acid • C, off-pathway intermediate • D, denatured state • I, on-pathway intermediate • N, native state

Article published online ahead of print. Article and publication date are at http://www.proteinscience.org/cgi/doi/10.1110/ps.041285605.

Reprint requests to: Daniel E. Otzen, Dept. of Life Sciences, Aalborg University, Sohngaardsholmsvej 49, DK-9000 Aalborg, Denmark; e-mail: dao{at}bio.aau.dk; fax: +45-98-14-18-08.


Add to CiteULike CiteULike   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us   Add to Digg Digg   Add to Reddit Reddit   Add to Technorati Technorati    What's this?


This article has been cited by other articles:


Home page
 Mol. Cell. ProteomicsHome page
M. O. Collins, L. Yu, I. Campuzano, S. G. N. Grant, and J. S. Choudhary
Phosphoproteomic Analysis of the Mouse Brain Cytosol Reveals a Predominance of Protein Phosphorylation in Regions of Intrinsic Sequence Disorder
Mol. Cell. Proteomics, July 1, 2008; 7(7): 1331 - 1348.
[Abstract] [Full Text] [PDF]

Home page
 J. Histochem. Cytochem.Home page
L. Lyck, I. Dalmau, J. Chemnitz, B. Finsen, and H. D. Schroder
Immunohistochemical Markers for Quantitative Studies of Neurons and Glia in Human Neocortex
J. Histochem. Cytochem., March 1, 2008; 56(3): 201 - 221.
[Abstract] [Full Text] [PDF]

Home page
 Am. J. Pathol.Home page
Y. J. C. Song, D. M.S. Lundvig, Y. Huang, W. P. Gai, P. C. Blumbergs, P. Hojrup, D. Otzen, G. M. Halliday, and P. H. Jensen
p25{alpha} Relocalizes in Oligodendroglia from Myelin to Cytoplasmic Inclusions in Multiple System Atrophy
Am. J. Pathol., October 1, 2007; 171(4): 1291 - 1303.
[Abstract] [Full Text] [PDF]

Home page
 Protein Sci.Home page
J. E. Mogensen, J. H. Kleinschmidt, M. A. Schmidt, and D. E. Otzen
Misfolding of a bacterial autotransporter
Protein Sci., November 1, 2005; 14(11): 2814 - 2827.
[Abstract] [Full Text] [PDF]


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Copyright © 2005 by The Protein Society.