Open AccessThe overlap between the thin‐ and thick‐filament reflections in the small‐angle X‐ray diffraction pattern from a molluscan smooth muscle
Author(s) -
Tajima Y.,
Makino K.,
Hanyuu T.,
Wakabayashi K.,
Amemiya Y.
Publication year - 1999
Publication title -
journal of synchrotron radiation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.172
H-Index - 99
ISSN - 1600-5775
DOI - 10.1107/s0909049598015544
Subject(s) - protein filament , byssus , optics , diffraction , thin layer , thin film , materials science , physics , condensed matter physics , layer (electronics) , biology , composite material , mytilus , nanotechnology , ecology
Small‐angle X‐ray diffraction studies of the living anterior byssus retractor muscle (ABRM) of Mytilus edulis have been carried out using a long (2.2 m) point‐focusing camera to investigate the overlap between the thin‐ and thick‐filament reflections. While the reflections due to the cross‐bridge lattice on the thick filaments in the resting ABRM are distant in the axial direction from the thin‐filament layer lines, the paramyosin cores of the thick filaments produce reflections very close to the thin‐filament reflections at axial spacings of 387, 59 and 51 Å. Using such a long camera it becomes possible to separate these reflections due to an improvement in the angular resolution and increase in the difference between the widths of the thin‐ and thick‐filament reflections, and it is shown that the intensities of the 387 and 59 Å thin‐filament layer lines gradually drop to zero close to the meridian. It becomes relatively easy to observe the thin‐filament‐based X‐ray pattern by use of the long camera, making it possible to show a partial resemblance of the small‐angle X‐ray pattern from the contracting ABRM with the pattern from the rigorized ABRM.