Desmin-binding specificities of two desmin CNBr fragments that correspond to the headpiece domain and Helix 1B

Patterns of abnormal protein expression in target formations and unstructured cores

Streaming of Z-disks and focal myofibrillar degeneration occur in target formations (TF) and unstructured cores (UC). Similar myofibrillar alterations are also part of the spectrum of ultrastructural reactions that can occur in the myopathies associated with myofibrillar degeneration and abnormal foci of desmin positivity. In the latter disorders, there is ectopic overexpression of dystrophin, neural cell adhesion molecule (NCAM), gelsolin, beta-amyloid precursor protein (beta APP) epitopes, alpha 1-antichymotrypsin (alpha 1-ACT), and many abnormal fiber regions are also strongly congophilic. Therefore, we searched for similar abnormalities in TF and UC. The UC and the center of TF show increased immunoreactivity for actin, alpha-actinin, gelsolin, dystrophin, beta APP epitopes, alpha 1-ACT, beta 2-microglobulin, desmin, and NCAM, but minimal or no congophilia. The periphery of the TF reacts strongly for nebulin but not for actin. The observed immunocytochemical alterations in TF and UC may represent a stereotyped cellular response associated with myofibrillar degeneration due to any cause. However, the three-dimensional profile of the TF and UC as well as their fiber-type specificity distinguish them from lesions that have similar immunocytochemical profiles in other myopathies.

Preparation and characterization of fragments from the N-terminal end of bovine serum albumin under native conditions

The domain I of BSA, containing residues 1-183 of the protein sequence, was isolated by CNBr treatment. It was further reductively cleaved into two subfragments, N1 and N2, in 8 M urea; the subfragments were regenerated in GSH and GSSG. The fragment N and subfragments N1 and N2 were found to be homogeneous with respect to size and charge. Results for amino acid composition, N-terminal amino acid sequence, thiol groups and M(r) suggested that the fragments N1 and N2 contain residues 88-183 and 1-87 of the intact BSA respectively. Optical studies, intrinsic-viscosity measurements, gel-filtration data and derived hydrodynamic parameters, taken together with the results on proteolytic digestion, showed that fragment N, as well as its subfragments N1 and N2, exist in compact and globular conformation and that the conformation of N2 fragment is more compact than that of the N1 fragment.