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Titin: Quantitative mass measurements by scanning transmission electron microscopy and structural implications for the sarcomere matrix of skeletal muscle
Author(s) -
Hainfeld James F.,
Wall Joseph S.,
Wang Kuan
Publication year - 1988
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(88)81321-8
Subject(s) - titin , sarcomere , skeletal muscle , transmission electron microscopy , obscurin , myofibril , biophysics , materials science , matrix (chemical analysis) , chemistry , anatomy , myocyte , biology , nanotechnology , microbiology and biotechnology , composite material , biochemistry
Scanning transmission electron microscopy has been used to investigate mass and linear mass density of native titin‐2, a large soluble fragment of intact titin, from rabbit skeletal muscle. Dark field images of unstained, freeze‐dried titin‐2 appeared as either compact globules or looser and larger balls of string. Direct mass measurements indicated that the compact forms have an average mass of 2.40±0.50 × 10 6 Da. The mass to length ratio, determined from well‐spread portions of titin strands (3–5 nm wide) from the ball of string forms, averaged 2.7±0.9 kDa/nm. Thus a single native intact titin molecule has a calculated contour length of well above ∼1 μm, sufficient to span unidirectionally between the Z line and M line region in a resting‐length sarcomere.