title: Effects of two stabilizing substitutions, D137L and G126R, in the middle part of α-tropomyosin on the domain structure of its molecule.
abstract: We applied differential scanning calorimetry (DSC) to investigate the effects of substitutions D137L and G126R (i.e. replacement of conserved non-canonical residues Asp137 and Gly126 by canonical ones) in the middle part of tropomyosin (Tm), as well as the combined one, D137L/G126R, on the thermal unfolding of Tm. Special approaches (e.g. combination of DSC with measurements of temperature dependences of pyrene excimer fluorescence) were applied to assign separate thermal transitions (calorimetric domains) on the DSC profiles to the certain parts of Tm molecule. The results show that substitutions D137L and G126R (and, especially, the combined one, D137L/G126R) may stabilize not only the middle region of Tm, but also the other parts of its molecule including N- and C-terminal parts. These results suggest that the stabilization of the Tm middle part can be transmitted along the coiled-coil length displaying long-range effects.
authors.affiliation: A.N. Bach Institute of Biochemistry, Russian Academy of Sciences, Leninsky prosp. 33, 119071 Moscow, Russia; Department of Biochemistry, School of Biology, Moscow State University, Russia.
authors.forename: Alexander M
authors.initials: AM
authors.lastname: Matyushenko
authors.affiliation: A.N. Bach Institute of Biochemistry, Russian Academy of Sciences, Leninsky prosp. 33, 119071 Moscow, Russia.
authors.forename: Natalia V
authors.initials: NV
authors.lastname: Artemova
authors.affiliation: A.N. Bach Institute of Biochemistry, Russian Academy of Sciences, Leninsky prosp. 33, 119071 Moscow, Russia.
authors.forename: Nikolai N
authors.initials: NN
authors.lastname: Sluchanko
authors.affiliation: A.N. Bach Institute of Biochemistry, Russian Academy of Sciences, Leninsky prosp. 33, 119071 Moscow, Russia; A.N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Russia. Electronic address: Levitsky@inbi.ras.ru.
authors.forename: Dmitrii I
authors.initials: DI
authors.lastname: Levitsky
mesh_terms: D019943:Amino Acid Substitution; D002152:Calorimetry, Differential Scanning; D017434:Protein Structure, Tertiary; D058767:Protein Unfolding; D011721:Pyrenes / Q000737:chemistry; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics; D013050:Spectrometry, Fluorescence; D044366:Transition Temperature; D014335:Tropomyosin / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism
chemical_list: D011721:Pyrenes; D011994:Recombinant Proteins; D014335:Tropomyosin; C030984:pyrene
keywords: Coiled-coil stabilization; Differential scanning calorimetry; Domain structure; Pyrene excimer fluorescence; Thermal unfolding; Tropomyosin