Structural and Functional Peculiarities of Cytoplasmic Tropomyosin Isoforms, the Products of and Genes.

Tropomyosin (Tpm) is one of the major protein partners of actin. Tpm molecules are -helical coiled-coil protein dimers forming a continuous head-to-tail polymer along the actin filament. Human cells produce a large number of Tpm isoforms that are thought to play a significant role in determining actin cytoskeletal functions.

Structural and Functional Effects of Cardiomyopathy-Causing Mutations in the Troponin T-Binding Region of Cardiac Tropomyosin.

Hypertrophic cardiomyopathy (HCM) is a severe heart disease caused by missense mutations in genes encoding sarcomeric proteins of cardiac muscle. Many of these mutations are identified in the gene encoding the cardiac isoform of tropomyosin (Tpm), an α-helical coiled-coil actin-binding protein that plays a key role in Ca-regulated contraction of cardiac muscle. We employed various methods to characterize structural and functional features of recombinant human Tpm species carrying HCM mutations that lie either within the troponin T-binding region in the C-terminal part of Tpm (E180G, E180V, and L185R) or near this region (I172T).

NADP-Dependent Aldehyde Dehydrogenase from Archaeon : Structural and Functional Features.

We present the functional and structural characterization of the first archaeal thermostable NADP-dependent aldehyde dehydrogenase AlDHPyr1147. , AlDHPyr1147 catalyzes the irreversible oxidation of short aliphatic aldehydes at 60-85°С, and the affinity of AlDHPyr1147 to the NADP+ at 60°С is comparable to that for mesophilic analogues at 25°С. We determined the structures of the apo form of AlDHPyr1147 (3.

The interchain disulfide cross-linking of tropomyosin alters its regulatory properties and interaction with actin filament.

Tropomyosin (Tpm) is an α-helical coiled-coil actin-binding protein that plays a key role in the Ca-regulated contraction of striated muscles. Two chains of Tpm can be cross-linked by formation of a disulfide bond between Cys-190 residues. Normally, the SH-groups of these residues in cardiac muscle are in reduced state but in heart pathologies the interchain cross-linking of Tpm was shown to occur.

Heat-induced conformational changes of TET peptidase from crenarchaeon Desulfurococcus kamchatkensis.

The effects of heating on the structure and stability of multimeric TET aminopeptidase (APDkam589) were studied by differential scanning calorimetry, tryptophan fluorescence quenching, and dynamic light scattering. Thermally induced structural changes in APDkam589 were found to occur in two phases: local conformational changes, which occur below 70 °C and are not associated with thermal denaturation of the protein, and global structural changes (above 70 °C) induced by irreversible thermal unfolding of the protein accompanied by its spontaneous aggregation. These results may explain the bell-shaped temperature dependence with a maximum at ~70 °C previously observed for enzymatic activity of APDkam589.