Designing a Single Protein‐Chain Reporter for Opioid Detection at Cellular Resolution

A protein chain can correspond to a monomeric protein or it can form, together with other chains, oligomeric assemblies, which can be either homo-oligomers or hetero-oligomers. In the latter case, the three-dimensional structure of the single protein chain is unlikely to be determined, since it will probably be difficult to express and crystallize. A computational method is presented here that allows one to predict if a chain participates in hetero-oligomeric assemblies, on the basis of its amino acid composition, with accuracy close to 80%. Such a technique should improve the success rate of structural biology projects.

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CHARACTERIZATION OF FIBRINOGEN RECEPTORS ASSOCIATED WITH GLTCCPROIEIN IIb/IIIa (GPIIb/GPIIIa) COMPLEX BY TRIGRAMIN, A UNIQUE LOW MOLECULAR WEIGHT PEPTIDE PROBE

10.1055/s-0038-1643523 ◽

1987 ◽

Author(s):

Tur-Fu Huang ◽

H Lukasiewicz ◽

C J Holt ◽

S Niewiarowski

Keyword(s):

Molecular Weight ◽

Monoclonal Antibodies ◽

Platelet Aggregation ◽

Low Molecular Weight ◽

Protein Chain ◽

Gamma Chain ◽

Peptide Probe ◽

Single Protein ◽

Similar Peptide

Trigramin (Mr weight 10 kDa), an acidic, cysteine rich peptide purified into homogeneity from Trimeresurus gramineus snake venom contained a single protein chain with EAGE at the NH2 terminal end. It inhibited platelet aggregation induced by various agents without affecting release reaction. It blocked competitively the binding of 125I-fibrincgen to AEP stimulated and chymotrypsin treated platelets (Ki= 2 × 10−8). 125-I trigramin bound to intact and to AEP stimulated platelets in a saturable manner (approx. 16,000 sites per platelet). However, AEP increased 5 fold, the binding affinity of trigramin to platelets (to Kd = 4 × 10−8M) suggesting that AEP is changing the conformation of receptors associated with GPIIb/GPIIIa complex. The binding of trigramin to thran-basthenic platelets was markedly reduced. The binding to normal platelets was significantly inhibited by EDTA and by monoclonal antibodies directed against GPIIb/GPIIIa complex but not by the antibodies directed against GPIIb or GPIIIa molecules. The binding of 125I-trigramin to AEP-stimulated platelets was inhibited by RGES (IC50 = 125 μM) and by YHHLGGAKOAGDV (C-terminal fragment of fibrinogen gamma chain, IC50 = 250 μM) suggesting that these or similar peptide sequences are required for interactions of various ligands with GPIIb/GPIIIa complex

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Orientation of actin filaments during motion in motility assay

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100136635 ◽

1995 ◽

Vol 53 ◽

pp. 52-53

Author(s):

J. Borejdo ◽

S. Burlacu

Keyword(s):

Actin Filaments ◽

Thin Filament ◽

Striated Muscle ◽

Myosin Head ◽

Classical Method ◽

Polarization Of Fluorescence ◽

Single Protein ◽

Intracellular Organelles ◽

Change Orientation ◽

Active Entity

Polarization of fluorescence is a classical method to assess orientation or mobility of macromolecules. It has been a common practice to measure polarization of fluorescence through a microscope to characterize orientation or mobility of intracellular organelles, for example anisotropic bands in striated muscle. Recently, we have extended this technique to characterize single protein molecules. The scientific question concerned the current problem in muscle motility: whether myosin heads or actin filaments change orientation during contraction. The classical view is that the force-generating step in muscle is caused by change in orientation of myosin head (subfragment-1 or SI) relative to the axis of thin filament. The molecular impeller which causes this change resides at the interface between actin and SI, but it is not clear whether only the myosin head or both SI and actin change orientation during contraction. Most studies assume that observed orientational change in myosin head is a reflection of the fact that myosin is an active entity and actin serves merely as a passive "rail" on which myosin moves.

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