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Biomedical subjects

M Klingenberg

Publications and source records attributed to M Klingenberg.

At least 109 records · Page 6Linked to original sources
PubMed1982

Some characteristics of the isolated ADP/ATP carrier.

The primary structure of the ADP/ATP carrier, comprising 297 amino acids, is discussed. Other structural features include the conformational changes related to the translocational process. Fluorescent adenine nucleotide analogs, DAN-AMP, DAN-ADP and DAN-ATP are being used for probing the transition between the "c" and "m" states. The fluorescent properties of the binding give strong support to the gated pore model, with "opposite" binding interfaces between substrate and carrier.

Amino Acid Sequence↗
PubMed1982

Complete amino acid sequence of the ADP/ATP carrier from beef heart mitochondria.

The complete primary structure of the ADP/ATP carrier from beef heart mitochondria is described. Cyanogen bromide cleaves the protein into a long, N-terminally blocked fragment with Mr 22,000 (CB1) and several small peptides. The primary information was derived from liquid-phase sequencing of tryptic peptides obtained from the maleylated carrier protein and the citraconylated CB1 fragment, as well as from cleavage products with Staphylococcus aureus protease. The multitude of thermolysinolytic, tryptic, chymotryptic and peptic peptides was sequenced by manual methods. They rendered overlaps and further supported already known partial sequences. Also, the bridge between the published acidolytic C-terminal fragment A2 was thus obtained.

Amino Acid Sequence↗
PubMed1981

Amino acid sequence determination of the ADP,ATP carrier from beef heart mitochondria. The sequence of the C-terminal acidolytic fragment.

The primary structure of the C-terminal region (94 residues) of the ADP,ATP carrier of beef heart mitochondria is described. CNBr cleavage results in a large peptide (CB1) with Mr 22 000 and several small peptides (CB2 to CB8). Peptide separation was achieved by gel chromatography with 80% formic acid or with an ethanol/formic acid mixture. The amino acid sequence of the small CNBr peptides was determined by solid-phase techniques. Hydrolysis in formic acid cleaves the carrier protein into an Mr 23 000 fragment (A1) with the blocked N-terminus and an Mr 10 000 fragment (A2) starting with proline. The alignment of two CNBr fragments was possible by degradation of A2 by solid-phase methods for 34 steps. The remaining CNBr fragments were arranged by sequencing the tryptic peptides of citraconylated A2.

Amino Acid Sequence↗
PubMed1981

Membrane protein oligomeric structure and transport function.

Proteins which traverse membranes tend to have a dimeric structure in which the dimer is arranged asymmetrically across the membrane with the axis of symmetry perpendicular to the membrane plane. This general structure is well suited to the function of transporting nutrients across the cell membrane.

Carrier Proteins↗
PubMed1979

Studies of the ADP/ATP carrier of mitochondria with fluorescent ADP analogue formycin diphosphate.

The ADP/ATP carrier was studied by a fluorescent substrate, formycin diphosphate which is the only fluorescent ADP analogue to bind. Its low quantum yield, short decay time and spectral overlap with tryptophan has as yet prevented its wider use. By incorporating fluorescent acceptors of formycin diphosphate fluorescence, anthracene-maleimide and vinylanthracene, into the membrane, these difficulties were circumvented. Only bound formycin diphosphate transfers energy to the probes so that the secondary emission of these probes is a measure for membrane-bound formycin diphosphate. The fluorescent transfer is inhibited by ADP, bongkrekate and carboxyatractylate whether added before or after incubation of formycin diphosphate showing that only binding to the adenine nucleotide carrier is measured. It also shows directly that the earlier demonstrated ADP fixation by bongkrekate is indeed a displacement into the matrix. The fluorescence decay time of the bound formycin diphosphate is measured as 1.95 ns compared to 0.95 ns of the free formycin diphosphate, indicating that formycin diphosphate is bound at the carrier in a non-polar environment. The depolarization decay time was found to be larger than 15 ns, indicating that carrier-bound formycin diphosphate is immobile within this time period.

Adenosine Diphosphate↗