Protein molecule, interactions with

Intermolecular interaction measurements. The functional properties are dependent on the protein molecules interacting with others of their own kind or with dissimilar ones (24, 51. 

All these alterations, which may be induced when a protein molecule interacts with a membrane surface either during convective (filtration) processes or under diffusive... 

Physical properties of the protein follow from the way individual protein molecules interact with water and with each other. 

Interactions among specific sequences of side chains give each protein a certain shape with unique chemical properties. A common shape found within many proteins is an a-helix shown to the right. Physical properties of the protein follow from the way individual protein molecules interact with water and with each other. 

In interpreting adsorption isotherms, a distinction should be made between very low coverage (initial part of the isotherm), where the protein molecules interact with the sorbent surface only, and high surface coverage (adsorption plateau), where lateral interactions between the adsorbed molecules play a role as well. 

All of these alterations, which may be induced when a protein molecule interacts with a membrane surface either during convective (filtration) processes or under diffusive conditions, can be reported by intrinsic fluorescence probes such as tryptophan residues and detected by using appropriate fluorescence techniques. In fact, the use of these techniques and the correct interpretation of their response is only possible when the number of tryptophan residues present in the protein is relatively low (one or two) because, otherwise, it becomes extremely difficult to assign a given fluorescence response to the corresponding tryptophan, limiting the interpretation effort. 

It is well known the tendency of polysaccharides to associate in aqueous solution. These molecular associations can deeply affect their function in a particular application due to their influence on molecular weight, shape and size, which determines how molecules interact with other molecules and water. There are several factors such as hydrogen bonding, hydrophobic association, an association mediated by ions, electrostatic interactions, which depend on the concentration and the presence of protein components that affect the ability to form supramolecular complexes. 

Complement is not a single protein but comprises a group of functionally linked proteins that interact with each other to provide mar of the effector functions of humoral immunity and inflammation. Most of the components of the system are present in the serum as proenzymes, i.e. enzyme precursors. Activation of a complement molecule occurs as a result of proteolytic cleavage of the molecule, which in itself confers proteolytic activity on the molecule. Thus, many components of the system serve as the substrate of a prior component and, in turn, activate a subsequent component. This pattern of sequential activation results in the system being called the complement cascade. ... 

Intracellular replication of viral particles depends entirely upon successful intracellular transcription of viral genes with subsequent translation of the viral mRNA. Translation of viral or cellular mRNA is dependent upon ribosome formation. Normally, several constituent molecules interact with each other on the mRNA transcript, forming the smaller ribosomal subunit. Subsequent for-mation/attachment of the larger subunit facilitates protein synthesis. 

The dipole-dipole interactions of the fluorophore in the electronic excited state with the surrounding groups of atoms in the protein molecule or with solvent molecules give rise to considerable shifts of the fluorescence spectra during the relaxation process. These spectral shifts may be observed directly by time-resolved spectroscopic methods. They may be also studied by steady-state spectroscopic methods, but in this case additional data must be obtained by varying factors that affect the ratio between tf and xp. 

Phosphopantetheine tethering is a posttranslational modification that takes place on the active site serine of carrier proteins - acyl carrier proteins (ACPs) and peptidyl carrier proteins (PCPs), also termed thiolation (T) domains - during the biosynthesis of fatty acids (FAs) (use ACPs) (Scheme 23), polyketides (PKs) (use ACPs) (Scheme 24), and nonribosomal peptides (NRPs) (use T domain) (Scheme 25). It is only after the covalent attachment of the 20-A Ppant arm, required for facile transfer of the various building block constituents of the molecules to be formed, that the carrier proteins can interact with the other components of the different multi-modular assembly lines (fatty acid synthases (FASs), polyketide synthases (PKSs), and nonribosomal peptide synthetases (NRPSs)) on which the compounds of interest are assembled. The structural organizations of FASs, PKSs, and NRPSs are analogous and can be divided into three broad classes the types I, II, and III systems. Even though the role of the carrier proteins is the same in all systems, their mode of action differs from one system to another. In the type I systems the carrier proteins usually only interact in cis with domains to which they are physically attached, with the exception of the PPTases and external type II thioesterase (TEII) domains that act in trans. In the type II systems the carrier proteins selectively interact... 

Polymer/Surfactant Interactions. Interaction between polymers and surfactants was recently reviewed by Robb (11) and surfactant association with proteins by Steinhardt and Reynolds (12). Polymer/surfactant interactions are highly dependent on the chemical nature of the polymer and the surfactant. In general, surfactants tend to associate with uncharged polymers in aggregates rather than individual surfactant molecules interacting with the macro-molecule. The ability of surfactants to form micelles is thought to be an important factor in the role of surfactant behavior in interactions with polymers. Individual surfactant... 

J. A. Loo, V. Thanabal, H.-Y. Mei Studying noncovalent small molecule interactions with protein and RNA targets by mass spectrometry. Mass Spectrom. Biol. Med. 2000, 2000,... 

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