Translocators description

A. General description Denileukin dif-titox is a recombinant, DNA-derived, interleukin-2 receptor specific ligand, cytotoxic fusion protein consisting of diphtheria toxin fragments A and B fused to interleukin-2. It is produced by expression of a recombinant fusion protein in Escherichia coli that contains nucleotide sequences for human interleukin-2, and sequences for the enzymatically active fragment A of diphtheria toxin and the membrane-translocating portion of diph-... 

As indicated previously, the final disposition of a chemical in the environment is dependent on the environmental conditions, characteristics of the media involved, and the various physicochemical properties of the contaminants. Table 6.6 provides a listing of properties describing the chemical, medium, and potential for translocation and transformation. This section focuses on chemical properties that are frequently used to assess the fate of a contaminant in air, water, soil, or biota. The goals of this section are to provide brief descriptions of relevant properties of a contaminant and to directly link specific ranges of these properties to predicted fate in the environment. 

Thirty years of research with bacteriorhodopsin has provided answers to many questions about how protons are transported by transmembrane pumps. In this small seven-transmembrane protein, absorption of light by the retinal chromophore Initiates a reaction cycle in which the initial state recovers through multiple conformational changes of the retinal and the protein, and a proton Is translocated stepwise from one side of the membrane to the other. Spectroscopy, extensive use of site-specific mutations, and crystallography have defined the photocycle reactions in atomic detail and provide a step-by-step description of the proton transfers, the transient local and global perturbations in the protein and how they arise, and the energy flow through the system, which add up to the mechanism of the pump. 

For the MNET description we take the presently most widely accepted model for this process as a basis the chemiosmotic model of Mitchell [37]. It comprises three elemental reactions in the mitochondrial membrane (apart from the translocators bringing the substrates to the active site of the enzymes acting upon them) (cf.. Fig. 1.3). The membrane itself is supposed to have a certain permeability to protons. The ATP synthase is a reversible pump, that pumps a certain number of protons... 

ABC transporters translocate many different allocrites (transport substrates), but the primary structures of the NBDs show --25% sequence identity across the whole superfamily [9[. Marked sequence conservation is observed over five short regions found in the NBDs (i) the Walker A and (ii) Walker B regions, which are separated by approximately 90-120 amino acids and between which lie the (hi) signature motif [2, 7, 9, 35, 36] and (iv) the glutamine loop (Q-loop) [37[. The most C-terminal motif is the histidine loop (H-loop) [2[. The signature, Q-loop, and H-loop seem to be specific to ABC transporters [9], and the function of these is described in more detail below. A recent description of the importance of a highly conserved aromatic residue has led to the naming of an A-loop at the N-terminus of the NBD [38[. 

The answer is b. (Murray, pp 812—828. Scriver, pp 3—45. Sack, pp 57-84. Wilson, pp 123-148.) Cytogenetic notation provides the chromosome number (e.g., 46), the sex chromosomes, and a shorthand description of anomalies. Examples include the following 45,X indicates a female with monosomy X or Turner s syndrome 47,XX-I-2I indicates a female with trisomy 21 or Down s syndrome 46,XX,t(14 21) indicates a female with translocation Down s syndrome 45,XX—21 indicates a female with mono-... 

Ribosome function is complex numerous cofactors are required for initiation, elongation, and termination (for a detailed description please see ref 33). Independent functions can be ascribed to the two subunits. Peptide bond formation takes place on the 50S subunit within the peptidyl transferase center, whereas decoding of the mRNA takes place on the 308 subunit within the decoding A- and P-sites. tRNAs in the P-site and the A-site span both subunits and couple the two events. After each round of peptide bond formation, a translocation step takes place that involves the movement of the mRNA through the ribosome, transfer of the P-site tRNA to the E (or exit)-site, and transfer of the A-site tRNA to the P-site. Most antibiotics target one of the listed steps decoding at either the A-site or the P-site, peptide bond formation within the peptidyl transferase center, or translocation. 

Mitochondria contain two aqueous compartments, one impermeable to sucrose and the other permeable to sucrose but impermeable to high-molecular-weight polysaccharides. This description was proposed by Werkheiser and Bartley (I) in 1956. Their conclusion that mitochondria consist of two membrane-enclosed compartments, one inside the other, is universally accepted today. Translocation across the inner membrane is performed by a host of specific transport systems whereas movement across the outer membrane occurs via a protein, called voltage-dependent anion-... 

Although s-BLMs on metallic substrates are attractive for certain purposes, as will be described later in this chapter, the metallic substrate, however, precludes ion translocation across the lipid bilayer. Therefore, the pursuit of a simple method for obtaining long-lived, planar BLMs separating two aqueous media has been elusive until a few years ago [17, 28-30]. A brief description of forming a planar BLM on hydrogel substrates is given below. 

Recently, the author advocated the application of the systems approach in the analysis and synthesis of a biotechnological process ( 1). The hierarchy of a biological system involves structural, functional, descriptive, control and dynamic organization. Structural and functional hierarchies of a biotechnological process are depicted in Tables I and II. In Table II a compartmental level is omitted. This is possible as long as the translocation of substances between organelles and cytoplasm is not important. The scheme of functions should be understood in both directions,... 

Thirteen years following the original description of the t(15 17) chromosomal rearrangement that has become the diagnostic hallmark of APL, the translocation breakpoint region was ultimately characterized and cloned. This was achieved by two distinct strategies Borrow et al. employed a physical-... 

This turnover includes the stages of the hyaluronan synthase-2 gene activation for the transcriptions of the enzyme s mRNA, enzyme incorporation into cytoplasmic membrane followed by the synthesis and direct translocation of HA into intercellular space, further transport from the intercellular space into the nucleus and fulfilment of the functions required for reconstruction, motion and organization of chromosomes in the nucleus. There is not yet sufficient experimental data to surely confirm this common picture, but from the data available it is possible to suggest such a description. This conclusion provides directions for further experimental research. 

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