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D A Winkelmann

Publications and source records attributed to D A Winkelmann.

26 records · Page 2Linked to original sources
PubMed1984

Crystallization of myosin subfragment 1.

Crystals of myosin subfragment 1 from avian skeletal muscle have been grown reproducibly. They diffract x-rays to at least 4.5-A resolution. The subfragment 1 crystallizes in space group P2(1)2(1)2(1) where a = 107 A, b = 117 A, and c = 278 A. The cell dimensions and intensity distribution on x-ray diffraction photographs are consistent with two molecules in the crystallographic asymmetric unit. Electrophoretic analysis shows that the myosin subfragment 1 present in the crystals contains a 95-kilodalton heavy chain fragment and both the essential and regulatory light chains.

Actins↗
PubMed1983

Immunochemical accessibility of ribosomal protein S4 in the 30 S ribosome. The interaction of S4 with S5 and S12.

The reactivity of protein S4-specific antibody preparations with 30 S ribosomal subunits and intermediates of in vitro subunit reconstitution has been characterized using a quantitative antibody binding assay. Anti-S4 antibody preparations did not react with native 30 S ribosomal subunits; however, they did react with various subunit assembly intermediates that lacked proteins S5 and S12. The inclusion of proteins S5 and S12 in reconstituted particles resulted in a large decrease in anti-S4 reactivity, and it was concluded that proteins S5 and S12 are primarily responsible for the masking of S4 antigenic determinants in the 30 S subunit. The effect of S5 and S12 on S4 accessibility is consistent with data from a variety of other approaches, suggesting that these proteins form a structural and functional domain in the small ribosomal subunit.

Antibodies, Bacterial↗
PubMed1983

Monoclonal antibodies localize changes on myosin heavy chain isozymes during avian myogenesis.

Monoclonal antibodies were used to identify and localize by immunoelectron microscopy epitopes on myosin isozymes. An antibody that reacts with an amino-terminal fragment of the myosin heavy chain maps on the myosin head 140 A distal to the head-rod junction. It identifies an epitope that is shared on adult and embryonic myosin, and detects two transitions in myosin expression during avian pectoralis myogenesis. Another antibody maps to the carboxyl terminus of the myosin rod. It is specific for an adult fast myosin epitope that is not detected in early developing pectoralis muscle. In contrast, an epitope that is present throughout development is identified by an antibody that reacts with a myosin light chain. This light chain epitope is localized at the head-rod junction. These results demonstrate structural changes in widely separated regions of the myosin molecule accompanying the sequential expression of developmental myosin isozymes.

Animals↗
PubMed1982

Ribosomal protein S4 is an internal protein: Localization by immunoelectron microscopy on protein-deficient subribosomal particles.

The location of protein S4 in the small ribosomal subunit has been identified by immunoelectron microscopy. Although intact small subunits are not reactive with antibodies directed against protein S4, subribosomal particles reconstituted without proteins S5 and S12 are reactive. By using these "incomplete" subparticles, we have mapped the position of S4. It is located at a single site on the exterior (cytoplasmic) side of the subunit, at the partition that separates the one-third, or head, from two-thirds, or base, of the subunit. In this location, protein S4 is "beneath" proteins S5 and S12. All three proteins are members of a complex on, or near, the external surface of the small ribosomal subunit that plays an important role in regulation of translational fidelity.

Electrophoresis, Polyacrylamide Gel↗
PubMedDate not supplied

A new myosin fragment: visualization of the regulatory domain.

Many of the functional domains of the myosin molecule have been defined by the use of proteolytic enzymes. Major fragments that retain enzymatic or assembly properties have been prepared by cleavage in the rod to form heavy meromyosin (HMM) and light meromyosin (LMM) or at the head-rod junction to form S-1 and rod. Limited tryptic digestion of vertebrate skeletal myosin S-1 indicates that the head contains three major regions: an amino-terminal nucleotide binding domain of molecular weight (MW) 25,000, a central domain of MW 50,000 and a carboxyl domain MW 20,000; the latter two are both able to bind to actin. Tryptic digestion of scallop S-1 has also been used to isolate a head fragment MW 14,000 associated with both types of scallop light chains. Here we report that myosin from vertebrate (chicken and rabbit skeletal) and molluscan (scallop adductor) striated muscles is cleaved in an unusual way with an enzyme from Pseudomonas aeruginosa. This bacterial protease (designated Ps-1) does not cleave myosin at the head-rod junction or in the rod; instead, Ps-1 splits the myosin heavy chain within the head, yielding a complete rod joined to the 20,000-MW head domains. The scallop regulatory and essential light chains remain associated with this fragment. We examined this new fragment by electron microscopy; the rods bear two 'nubs' about 100 A long, which appear to correspond morphologically to the neck region of the myosin molecule.

Animals↗
PubMedDate not supplied

A network-based prototype for interactive telemedicine & automated management of distributed, clinical databases.

A network-based prototype has been developed to automate the process of generating and maintaining distributed databases of medical images and clinical reports, and for conducting interactive consultation among disparate clinical and research sites irrespective of the architecture of interacting computers. Pathologists routinely interpret gross and microscopic specimens to tender diagnoses and to engage in a broad spectrum of research. This assessment process leads to clinical decisions often limited by time constraints and by the availability of local expertise. Consultation with peers at other institutions is typically achieved by direct transfer of slides rather than images. A network of heterogeneous computer platforms, graphical user interfaces, and operating systems was established to test the performance of the software. Clinical diagnoses rendered by pathologists using the prototypical system and software were consistent with those reported two years earlier using conventional light microscopy in more than 97% of the cases studied.

Clinical Laboratory Information Systems↗