New human erythrocyte protein with binding sites for both spectrin and calmodulin

Conference · Thu May 01 04:00:00 EDT 1986 · Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States)

OSTI ID:6985901

Gardner, K; Bennett, V

A new cytoskeletal protein that binds calmodulin has been purified to greater than 95% homogeneity from human erythrocyte cytoskeletons. The protein is a heterodimer with subunits of 103,000 and 97,000 and M/sub r/ = 197,000 calculated from its Stokes radius of 6.9 nm and sedimentation coefficient of 6.8. A binding affinity of this protein for calmodulin has been estimated to be 230 nM by displacement of two different concentrations of /sup 125/I-azidocalmodulin with increasing concentrations of unmodified calmodulin followed by Dixon plot analysis. This protein is present in red cells at approximately 30,000 copies per cell and contains a very tight binding site(s) on cytoskeletons. The protein can be only partially solubilized from isolated cytoskeletons in buffers containing high salt, but can be totally solubilized from red cell ghost membranes by extraction in low ionic strength buffers. Affinity purified IgG against this calmodulin-binding protein identifies crossreacting polypeptide(s) in brain, kidney, testes and retina. Visualization of the calmodulin-binding protein by negative staining, rotary shadowing and unidirectional shadowing indicate that it is a flattened circular molecule with molecular height of 5.4 nm and a diameter of 12.4 nm. Preliminary cosedimentation studies with purified spectrin and F-actin indicate that the site of interaction of this calmodulin-binding protein with the cytoskeleton resides on spectrin.

• Research Organization: Johns Hopkins Univ. School of Medicine, Baltimore, MD
• OSTI ID: 6985901
• Report Number(s): CONF-8606151-
• Conference Information: Journal Name: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States) Journal Volume: 45:6
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
AFFINITY
ANIMALS
BETA DECAY RADIOISOTOPES
BIOCHEMICAL REACTION KINETICS
BIOLOGICAL MATERIALS
BLOOD
BLOOD CELLS
BODY
BODY AREAS
BODY FLUIDS
BRAIN
CELL CONSTITUENTS
CELL MEMBRANES
CENTRAL NERVOUS SYSTEM
DAYS LIVING RADIOISOTOPES
ELECTRON CAPTURE RADIOISOTOPES
ERYTHROCYTES
EYES
FACE
GONADS
HEAD
INTERMEDIATE MASS NUCLEI
IODINE 125
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
KIDNEYS
KINETICS
MALE GENITALS
MAMMALS
MAN
MATERIALS
MEMBRANE PROTEINS
MEMBRANES
NERVOUS SYSTEM
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
ORGANS
PRIMATES
PROTEINS
PURIFICATION
RADIOISOTOPES
REACTION KINETICS
RECEPTORS
RETINA
SENSE ORGANS
TESTES
TRACER TECHNIQUES
VERTEBRATES