Document Detail


Modeling motility of the kinesin dimer from molecular properties of individual monomers.
MedLine Citation:
PMID:  18370409     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Conventional kinesin is a homodimeric motor protein that unidirectionally transports organelles along filamentous microtubule (MT) by hydrolyzing ATP molecules. There remain two central questions in biophysical studies of kinesin: (1) the molecular physical mechanism by which the kinesin dimer, made of two sequentially identical monomers, selects a unique direction (MT plus end) for long-range transport and (2) the detailed mechanisms by which local molecular properties of individual monomers affect the motility properties of the dimer motor as a whole. On the basis of a previously proposed molecular physical model for the unidirectionality of kinesin, this study investigates the synergic motor performance of the dimer from well-defined molecular properties of individual monomers. During cargo transportation and also in single-molecule mechanical measurements, a load is often applied to the coiled-coil dimerization domain linking the two motor domains ("heads"). In this study, the share of load directly born by each head is calculated, allowing for an unambiguous estimation of load effects on the ATP turnover and random diffusion of individual heads. The results show that the load modulations of ATP turnover and head diffusion are both essential in determining the performance of the dimer under loads. It is found that the consecutive run length of the dimer critically depends upon a few pathways, leading to the detachment of individual heads from MT. Modifying rates for these detachment pathways changes the run length but not the velocity of the dimer, consistent with mutant experiments. The run length may increase with or without the ATP concentration, depending upon a single rate for pure mechanical detachment. This finding provides an explanation to a previous controversy concerning ATP dependence of the run length, and related quantitative predictions of this study can be tested by a future experiment. This study also finds that the experimental observations for assisting loads can be quantitatively explained by load-biased head diffusion. We thus conclude that the dimer motility under resisting as well as assisting loads is governed by essentially the same mechanisms.
Authors:
Dagong Fan; Wenwei Zheng; Ruizheng Hou; Fuli Li; Zhisong Wang
Related Documents :
7723649 - Versaclimbing elicits higher vo2max than does treadmill running or rowing ergometry.
3781999 - Effect of graded erythrocythemia on cardiovascular and metabolic responses to exercise.
1487339 - Effect of short-term training cessation on performance measures in distance runners.
14767399 - Maximal but not submaximal performance is reduced by constant-speed 10-km run.
7458499 - Acute rhabdomyolysis associated with an echovirus 9 infection.
2596329 - The metabolic relation between hypoxanthine and uric acid in man following maximal shor...
3977809 - Effect of physical training in cool and hot environments on +gz acceleration tolerance ...
22382669 - The acute effects of aerobic exercise and modified rugby on inflammation and glucose ho...
7723649 - Versaclimbing elicits higher vo2max than does treadmill running or rowing ergometry.
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2008-03-28
Journal Detail:
Title:  Biochemistry     Volume:  47     ISSN:  0006-2960     ISO Abbreviation:  Biochemistry     Publication Date:  2008 Apr 
Date Detail:
Created Date:  2008-05-21     Completed Date:  2008-06-10     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0370623     Medline TA:  Biochemistry     Country:  United States    
Other Details:
Languages:  eng     Pagination:  4733-42     Citation Subset:  IM    
Affiliation:
Institute of Modern Physics, and Applied Ion Beam Physics Laboratory, Fudan University, Shanghai, China.
Export Citation:
APA/MLA Format     Download EndNote     Download BibTex
MeSH Terms
Descriptor/Qualifier:
Adenosine Triphosphate / metabolism
Diffusion
Dimerization
Kinesin / chemistry*,  metabolism*
Microtubules / metabolism
Models, Biological*
Protein Binding
Solutions
Viscosity
Chemical
Reg. No./Substance:
0/Solutions; 56-65-5/Adenosine Triphosphate; EC 3.6.1.-/Kinesin

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


Previous Document:  Incorporation of oxidized guanine nucleoside 5'-triphosphates in DNA with DNA polymerases and prepar...
Next Document:  The role of serine 167 in human indoleamine 2,3-dioxygenase: a comparison with tryptophan 2,3-dioxyg...