Document Detail


The AtMAP65-1 cross-bridge between microtubules is formed by one dimer.
MedLine Citation:
PMID:  17504815     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The microtubule-associated protein AtMAP65-1 from Arabidopsis thaliana dimerizes and forms 25 nm cross-bridges between microtubules, but the exact mechanism is unknown. Here, we used the predicted three-dimensional structure of AtMAP65-1 as a basis for analyzing the actual cross-bridging in detail. Fold-recognition predicts that AtMAP65-1 contains four coiled-coil domains and a flexible extended loop. The length of these coiled-coil domains is about 25 nm, suggesting that one molecule could span the gap, hence forming an antiparallel overlapping dimer instead of an end-to-end dimer. We then tested this model by using truncations of AtMAP65-1. EDC {[3-(dimethylamino) propyl] carbodiimide} cross-linking analysis indicated that the N-terminus of the rod domain of AtMAP65-1 (amino acids 1-339) binds to the C-terminus of the rod domain (amino acids 340-494) and also participates in connecting the two antiparallel proteins in the cross-bridge. Nevertheless, microtubules can still form bundles in the presence of AtMAP65-1 340-587 (amino acids 340-587) or AtMAP65-1 1-494 (amino acids 1-494). Comparing the cold stability of microtubule bundles induced by full-length AtMAP65-1 with that of AtMAP65-1 340-587 or AtMAP65-1 1-494, we conclude that AtMAP65-1 495-587 acts as a flexible extended loop, playing a crucial role in binding to and stabilizing microtubules in the AtMAP65-1 cross-bridge.
Authors:
Hua Li; Tonglin Mao; Ziding Zhang; Ming Yuan
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2007-05-15
Journal Detail:
Title:  Plant & cell physiology     Volume:  48     ISSN:  0032-0781     ISO Abbreviation:  Plant Cell Physiol.     Publication Date:  2007 Jun 
Date Detail:
Created Date:  2007-06-13     Completed Date:  2007-10-11     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  9430925     Medline TA:  Plant Cell Physiol     Country:  Japan    
Other Details:
Languages:  eng     Pagination:  866-74     Citation Subset:  IM    
Affiliation:
State Key Laboratory of Plant Physiology and Biochemistry, China Agricultural University, Beijing 100094, PR China.
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MeSH Terms
Descriptor/Qualifier:
Amino Acid Sequence
Arabidopsis / cytology,  metabolism*
Arabidopsis Proteins / chemistry*,  genetics,  metabolism*
Dimerization
Gene Expression Regulation, Plant
Microtubule-Associated Proteins / chemistry*,  genetics,  metabolism*
Microtubules / chemistry,  metabolism*
Models, Molecular
Molecular Sequence Data
Protein Binding
Protein Conformation
Chemical
Reg. No./Substance:
0/Arabidopsis Proteins; 0/MAP65-1 protein, Arabidopsis; 0/Microtubule-Associated Proteins

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