The complete amino acid sequence of the high molecular mass hemorrhagic protein HR1B isolated from the venom of Trimeresurus flavoviridis.

ABSTRACT The polypeptide and structural gene for a high-molecular-massc-type cytochrome, cytochromec 553O, was isolated from the methanotrophMethylococcus capsulatus Bath. Cytochromec 553O is a homodimer with a subunit molecular mass of 124,350 Da and an isoelectric point of 6.0. The hemec concentration was estimated to be 8.2 ± 0.4 mol of heme c per subunit. The electron paramagnetic resonance spectrum showed the presence of multiple low spin, S = 1/2, hemes. A degenerate oligonucleotide probe synthesized based on the N-terminal amino acid sequence of cytochrome c 553O was used to identify a DNA fragment from M. capsulatusBath that contains occ, the gene encoding cytochrome c 553O. occ is part of a gene cluster which contains three other open reading frames (ORFs). ORF1 encodes a putative periplasmic c-type cytochrome with a molecular mass of 118,620 Da that shows approximately 40% amino acid sequence identity with occand contains nine c-heme-binding motifs. ORF3 encodes a putative periplasmic c-type cytochrome with a molecular mass of 94,000 Da and contains sevenc-heme-binding motifs but shows no sequence homology toocc or ORF1. ORF4 encodes a putative 11,100-Da protein. The four ORFs have no apparent similarity to any proteins in the GenBank database. The subunit molecular masses, arrangement and number of hemes, and amino acid sequences demonstrate that cytochrome c 553O and the gene products of ORF1 and ORF3 constitute a new class of c-type cytochrome.

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A high molecular mass protein isolated from chicken gizzard: its localization at the dense plaques and dense bodies of smooth muscle and the Z-disks of skeletal muscle

Journal of Cell Science ◽

10.1242/jcs.108.3.857 ◽

1995 ◽

Vol 108 (3) ◽

pp. 857-868

Author(s):

A.G. Terasaki ◽

H. Nakagawa ◽

E. Kotani ◽

H. Mori ◽

K. Ohashi

Keyword(s):

Skeletal Muscle ◽

Smooth Muscle ◽

Amino Acid ◽

Amino Acid Sequence ◽

Molecular Mass ◽

Muscle Cells ◽

High Molecular Mass ◽

Dense Bodies ◽

Muscle Tissues ◽

Low Salt

We purified a 450 kDa protein from a low-salt alkaline extract of chicken gizzard smooth muscle. This high molecular mass protein could be extracted with the low-salt alkaline solution at 37 degrees C but not at 4 degrees C. The 450 kDa protein was isolated from the extract by ammonium sulfate fractionation and following sequential column chromatography using hydroxylapatite, DEAE-Cellulofine A-800m and phenyl-Sepharose CL-4B resins. The partially purified protein molecule resembled a flexible rod with a globular head and an irregular-shaped tail. Its length was approximately 300 nm. The nucleotide sequence of the partial cDNA encoding this protein was determined and analyzed with a data base. The analysis showed that the protein revealed significant homology with the rod region of chicken filamin (57% homology in amino acid sequence). Immunoblot analysis showed that an affinity-purified antibody reacted exclusively with the 450 kDa protein band of smooth, skeletal and cardiac muscle tissues. By indirect immunofluorescence microscopy, we examined the localization of the 450 kDa protein in smooth and skeletal muscle cells. The affinity-purified antibody against the 450 kDa protein stained the dense plaques and dense bodies of smooth muscle, the peripheral region of Z-disks and the subsarcolemmal region of skeletal muscle. Immunoelectron microscopy confirmed the localization of the 450 kDa protein at the peripheral regions of the actin anchoring structures mentioned above. Judging from its amino acid sequence, molecular size, molecular shape, immunological reactivity and localization in muscle cells, the 450 kDa protein seemed to be a new component associated with the actin-anchoring structures of muscle tissues.(ABSTRACT TRUNCATED AT 250 WORDS)

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