TY - JOUR
T1 - Hierarchical extensibility in the PEVK domain of skeletal-muscle titin
AU - Nagy, A.
AU - Grama, L.
AU - Huber, T.
AU - Bianco, P.
AU - Trombitás, K.
AU - Granzier, H. L.
AU - Kellermayer, M. S.Z.
N1 - Funding Information:
This work was supported by grants from the Hungarian Science Foundation (OTKA T037935), Hungarian Ministry of Education (BIO-110/2002), European Union (HPRN-CT-2000-00091), the South Trans-Danubian Co-operative Research Center to M.S.Z.K., and National Institutes of Health (HL062881/061497/067274) to H.G. M.S.Z.K. is a Howard Hughes Medical Institute International Research Scholar.
PY - 2005/7
Y1 - 2005/7
N2 - Titin is the main determinant of passive muscle force. Physiological extension of titin derives largely from its PEVK (Pro-Glu-Val-Lys) domain, which has a different length in different muscle types. Here we characterized the elasticity of the full-length, human soleus PEVK domain by mechanically manipulating its contiguous, recombinant subdomain segments: an N-terminal (PEVKI), a middle (PEVKII), and a C-terminal (PEVKIII) one third. Measurement of the apparent persistence lengths revealed a hierarchical arrangement according to local flexibility: the N-terminal PEVKI is the most rigid and the C-terminal PEVKIII is the most flexible segment within the domain, Immunoelectron microscopy supported the hierarchical extensibility within the PEVK domain. The effective persistence lengths decreased as a function of ionic strength, as predicted by the Odijk-Skolnick-Fixman model of polyelectrolyte chains. The ionic strength dependence of persistence length was similar in all segments, indicating that the residual differences in the elasticity of the segments derive from nonelectrostatic mechanisms.
AB - Titin is the main determinant of passive muscle force. Physiological extension of titin derives largely from its PEVK (Pro-Glu-Val-Lys) domain, which has a different length in different muscle types. Here we characterized the elasticity of the full-length, human soleus PEVK domain by mechanically manipulating its contiguous, recombinant subdomain segments: an N-terminal (PEVKI), a middle (PEVKII), and a C-terminal (PEVKIII) one third. Measurement of the apparent persistence lengths revealed a hierarchical arrangement according to local flexibility: the N-terminal PEVKI is the most rigid and the C-terminal PEVKIII is the most flexible segment within the domain, Immunoelectron microscopy supported the hierarchical extensibility within the PEVK domain. The effective persistence lengths decreased as a function of ionic strength, as predicted by the Odijk-Skolnick-Fixman model of polyelectrolyte chains. The ionic strength dependence of persistence length was similar in all segments, indicating that the residual differences in the elasticity of the segments derive from nonelectrostatic mechanisms.
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U2 - 10.1529/biophysj.104.057737
DO - 10.1529/biophysj.104.057737
M3 - Article
C2 - 15849252
AN - SCOPUS:23244452727
VL - 89
SP - 329
EP - 336
JO - Biophysical Journal
JF - Biophysical Journal
SN - 0006-3495
IS - 1
ER -