Proteins defined

Semaphorins are secreted, membrane-associated or transmembrane proteins defined by the presence of a sema-phorin protein domain (Serna domain). In the mammalian system, more than 20 semaphorins have been identified which play important roles in a variety of tissues. The best characterized receptors for mediating semaphoiin effects are members of the neuropilin and plexin families of transmembrane proteins. Semaphoiin functions are best described in the regulation of neural development, angiogenesis, immunoregulation and cancer. 

Tobin, D. et al. Combinatorial expression of TRPV channel proteins defines their sensory functions and subcellular localization in C. elegans neurons. Neuron 35 307-318,2002. 

Grozinger CM, Schreiber SL (2000) Regulation of histone deacetylase 4 and 5 and transcriptional activity by 14-3-3-dependent cellular localization. Proc Natl Acad Sci USA 97(14) 7835—7840 Grozinger CM, Hassig CA, Schreiber SL (1999) Three proteins define a class of human histone deacety-lases related to yeast Hdalp. Proc Natl Acad Sci USA 96(9) 4868 873 Guardiola AR, Yao TP (2002) Molecular cloning and characterization of a novel histone deacetylase HDACIO. J Biol Chem 277(5) 3350-3356... 

Primary structure the structure of a protein defined by the sequence of amino acids along the polypeptide backbone. 

Calculate % crude protein, defined as 6.25 x % nitrogen, or 5.7 x % nitrogen for wheat grains. 

Is and PBPRP1 may then represent an OBP-1 type of protein defined by key residues that may underlie specific functions. The ABPX/PBPRP-specific amino acid residues arginine at position 16, lysine at position 47, proline at position 76, threonine at position 92 are replaced respectively by leucine, glycine, lysine and lysine residues that are conserved in the different types of binding protein from B. mori (Krieger et al., 1993 Picimbon, 2001). These replacements may be relevant to support the function of ABPX. Based on the crystal structure of the bombykol-PBP complex, the tryptophane at position 101 and the valine 105 have been shown to contact the molecule of Bombykol (Sandler et al., 2000). These are replaced by two threonine residues characteristic of OBP-1. Therefore, the threonine residues characteristic of OBP Is may be of crucial importance for the binding specificities of these proteins. 

During recent decades, the use of artificial phospholipid membranes as a model for biological membranes has become the subject of intensive research. As discussed above, biological membranes are composed of complex mixtures of lipids, sterols, and proteins. Defined artificial membranes may therefore serve as simple models of membranes that have many striking similarities with biological membranes. A comparison of some important physicochemical properties of biological and artificial membranes is given in Table 1.8 [2]. 

Screening assays are designed for optimal sensitivity to avoid false negatives. For new proteins defining an absolute sensitivity is impossible because of lack of positive sera. An alternative approach is to set the cut point for the assay at the 5% false positive level using a panel of normal human sera and/or untreated patient sera representative of the groups to be treated. 

Chan, J.M., Wu, W., Dean, D.R., and Seefeldt, L.C. (2000) Construction and Characterization of a heterodimeric iron protein defining rolee for adenosin triphosphate in nitrogenase catalysis, Biochemistry 39, 7221-7228. 

The goal of protein-structure prediction is to derive the tertiary structure of the protein (defined as the manner in which the protein is bent or folded in three dimensions) given the sequence of amino acids (referred to as the primary structure). In between the primary and tertiary structure is the secondary structure which consists of regularly recurring arrangements of the protein chain in one-dimension (i e, a-helices and (3-sheets)... 

The HMW subunits are encoded by genes located on the group 1 chromosomes at loci designated Glu-Al, Glu-Bl and Glu-Dl. Each Glu-1 locus comprises two tightly linked genes encoding proteins defined on the basis of their molecular weights and... 

There are several results that support the conclusion that the conformation of a protein, defined as the backbone and internal arrangements, is similar in the dry state and in solution, to a resolution of perhaps 1 A. 

Ma JL, Kim EM, Haber JE, Lee SE. Yeast Mrell and Radi proteins define a Ku-independent mechanism to repair double-strand breaks lacking overlapping end sequences. Mol. Cell. Biol. 2003 23 8820-8828. 

Anderson P, Nagler-Anderson C, O Brien C, Levine H, Watkins S, Slayter HS, Blue ML, Schlossman SF (1990) A monoclonal antibody reactive with a 15-kDa cytoplasmic granule-associated protein defines a subpopulation of CD8-I- T lymphocytes. J Immunol 144 574-582. 

The object of this chapter is to provide some background for the appreciation of the pharmaceutics of proteins, peptides DNA, oligonucleotides and monoclonal antibodies as therapeutic entities. From an understanding of the nature of amino acids and their physical properties comes an appreciation of the physical nature and properties of peptides, polypeptides and proteins, defined below. The solution properties of proteins in simple and complex media should be understood, together with the factors affecting the stability of proteins in solution. Problems in the formulation of proteins to be overcome will then become clearer. 

To assign physical meaning to D, we associate D with the mass fractal dimension of the protein, defined by M LD. Then D is the slope of log M versus log L, where M is the mass of all protein atoms enclosed by concentric spheres of radius L. For a completely collapsed, space-filling polymer, D is 3, but D may be generally less than 3 in proteins due to a combination of compact structures and spacing between them. Figure 14 shows log M versus log L for cytochrome c. The concentric spheres of radius L are centered on one of the Ca s of the protein backbone. We compute M for values of L from 2 A to 16 A. The plot appears linear with slope 2.15. Continuing in this way, we compute... 

Information most probably entered nascent life with the appearance of RNA. One need only look at Figure 10.1 to realize that DNA can be dispensed with provided that RNA can be replicated. In such a DNA-free RNA world," RNA would have served both as the repository of genetic information and as the agent of the expression of this information, hrst by itself and later by way of its protein translation products. On the other hand, the key functions carried out by RNA molecules in protein synthesis indicate strongly that proteins - defined as special polypeptides made with a distinct set of twenty amino acids - are an invention of RNA. It has been proposed, because of the molecular complexity of RNA, that this substance may itself have been preceded by some simpler information-bearing molecule. This hypothesis, however, is unsupported by any evidence. 

Esclamado RM, Gown AM, Vogel AM. Unique proteins defined by monoclonal antibodies specific for human melanoma. Am J Surg. 1986 152 376-385. 

The prefactor, P, depends on the electronic coupling of donor and acceptor with the bridging orbitals. A correlation between p (cf. Eq. 3) and Ec (Eq. 4) is easily demonstrated An individual strand of a p-sheet protein defines a linear tunneling pathway along the peptide, spanning a distance (r — ro) of 0.34 nm per residue (three covalent bonds). Thus, inserting a p value of 10 nm in Eq. 3, the decay factor, Ec of Eq. 4 becomes 0.6 per covalent bond. 

For many proteins the functional form is not composed of a single peptide but is rather an aggregate of smaller globular peptides. For instance, the protein hemoglobin is composed of four individual globular peptide subunits two identical a-subunits and two identical fj-subimits. Only when the four peptides are bound to one another is the protein molecule functional. The association of several polypeptides to produce a functional protein defines the quaternary structure of a protein. 

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