Biomaterial Database

Purification and characterization of the 1,200-kDa subfragment of connectin filaments produced by 0.1 mM calcium ions. 1994

R Tanabe, and R Tatsumi, and K Takahashi

Department of Animal Science, Faculty of Agriculture, Hokkaido University.

When myofibrils prepared from chicken leg muscle were treated with a solution containing 0.1 mM CaCl2 and 30 micrograms/ml of leupeptin, alpha-connectin, which exists as a longitudinal thin filament in a sarcomere, was split into beta-connectin and a 1,200-kDa subfragment. The native subfragment was successfully purified without using any denaturant: It was extracted with 1 M KI solution from the Ca-treated myofibrils and purified by TSKgel G6000PW column chromatography. About 10 mg of the subfragment was yielded from 100 g of starting muscle. Using immunofluorescence microscopy and immunoelectron microscopy, we show here that polyclonal antibodies against the 1,200-kDa subfragment bind to the Z-disk and the epitope, which is about 0.34 micron apart from the Z-disk at a sarcomere length of 2.6 microns; the 1,200-kDa subfragment constitutes the proximal region of connectin filaments. Purified alpha-actinin decorated alpha-connectin and the 1,200-kDa subfragment on nitrocellulose blots of myofibrillar proteins separated by SDS-PAGE. Therefore, we conclude that connectin filaments are anchored to the Z-disk by the binding of the 1,200-kDa subfragment to alpha-actinin.

UI	MeSH Term	Description	Entries
D007976	Leupeptins	A group of acylated oligopeptides produced by Actinomycetes that function as protease inhibitors. They have been known to inhibit to varying degrees trypsin, plasmin, KALLIKREINS, papain and the cathepsins.
D008856	Microscopy, Fluorescence	Microscopy of specimens stained with fluorescent dye (usually fluorescein isothiocyanate) or of naturally fluorescent materials, which emit light when exposed to ultraviolet or blue light. Immunofluorescence microscopy utilizes antibodies that are labeled with fluorescent dye.	Fluorescence Microscopy,Immunofluorescence Microscopy,Microscopy, Immunofluorescence,Fluorescence Microscopies,Immunofluorescence Microscopies,Microscopies, Fluorescence,Microscopies, Immunofluorescence
D008970	Molecular Weight	The sum of the weight of all the atoms in a molecule.	Molecular Weights,Weight, Molecular,Weights, Molecular
D009124	Muscle Proteins	The protein constituents of muscle, the major ones being ACTINS and MYOSINS. More than a dozen accessory proteins exist including TROPONIN; TROPOMYOSIN; and DYSTROPHIN.	Muscle Protein,Protein, Muscle,Proteins, Muscle
D009210	Myofibrils	The long cylindrical contractile organelles of STRIATED MUSCLE cells composed of ACTIN FILAMENTS; MYOSIN filaments; and other proteins organized in arrays of repeating units called SARCOMERES .	Myofilaments,Myofibril,Myofilament
D010446	Peptide Fragments	Partial proteins formed by partial hydrolysis of complete proteins or generated through PROTEIN ENGINEERING techniques.	Peptide Fragment,Fragment, Peptide,Fragments, Peptide
D011485	Protein Binding	The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.	Plasma Protein Binding Capacity,Binding, Protein
D011494	Protein Kinases	A family of enzymes that catalyze the conversion of ATP and a protein to ADP and a phosphoprotein.	Protein Kinase,Kinase, Protein,Kinases, Protein
D002122	Calcium Chloride	A salt used to replenish calcium levels, as an acid-producing diuretic, and as an antidote for magnesium poisoning.	Calcium Chloride Dihydrate,Calcium Chloride, Anhydrous
D002352	Carrier Proteins	Proteins that bind or transport specific substances in the blood, within the cell, or across cell membranes.	Binding Proteins,Carrier Protein,Transport Protein,Transport Proteins,Binding Protein,Protein, Carrier,Proteins, Carrier