NA protein

Thus modifying the lysine amino group in yeast proteins using maleic or citraconic anhydride altered the NA-protein interactions and facilitated separating proteins from NAs at pH 4.2. 

Titrate the relative amounts of NA protein for the parent and variant NA samples using the MAb-based ELISA described in Subheading 3.3.2. 

The monoclonal NC-10 antibody only recognizes the native conformation of the NA from NWS/G70C (N9) virus hence, the calculation of NA specific activity is based on activity of only native NA. If a polyclonal antibody is used to capture the NA the activity will be based on total NA protein, not just native NA. In the case of our NA mutant this was critical, since the NA is unstable and activity calculations are grossly different if one calculates activity of total vs native NA protein. 

Although the A280 gives an approximate value for the total amount of NA protein, this does not necessarily represent native protein. Binding to an M Ab recognizing only the native NA is the only way of determining the relative amount of native NA protein. 

CW EPR spectroscopy is extensively used to probe local and global dynamics of nucleic acid molecules and to correlate these data with NA structures and functional aspects. This is particularly useful to investigate and monitor NA-protein or NA-ligand interactions. In the following we are going to highlight some recent applications of CW EPR to study RNA and DNA molecules. 

Elzoghby AO, Samy WM, Elgindy NA. Protein-based nanocarriers as promising dmg and gene delivery systems. J Control Release 2012 161(1) 38—49. 

X-ray crystal structures of type A (H3) HA, type C HEF protein and type A and B NA proteins have given unique insights into sialic acid binding and cleavage and guided the design of inhibitors based on knowledge of interactions between the proteins and their substrates. 

Dayhoff M 01978. A Model of Evolutionary Change. In Dayhoff M O (Editor) Proteins in A Has of F Sequence and Structure Volume 5 Supplement 3. Georgetown University Medical Center, Na Biomedical Research Foundation, pp. 345-358. 

The protein fraction is responsible for a major part of membrane function Non polar materials can diffuse through the bilayer from one side to the other relatively eas ily but polar materials particularly metal ions such as Na" K" and Ca " cannot The... 

Subunit vaccines based on the surface proteins of vims are also being explored. It has been demonstrated that the two major protective antigens are haemagglutinin (HA) and neuraminidase (NA). The genes for these antigens have been cloned and expressed in baculovims in insect cell culture (84). 

S ts can be used to precipitate proteins by salting out effects. The effectiveness of various salts is determined by the Hofmeister series, with anions being effective in the order citrate > PO4" > SO4" > CH3COO > Cl > NO3 , and cations according to NH4 > > Na ... 

CM Topham, N Snmvasan, CJ Thorpe, IP Ovenngton, NA Kalsheker. Comparative modelling of major house dust mite allergen der p I Structure validation using an extended environmental ammo acid propensity table. Protein Eng 7 869-894, 1994. 

The ionic species of the mobile phase will also affect the separation. This is shown in Table 4.3 by the difference in resolution values for magnesium chloride buffer compared to sodium sulfate buffer. In addition, calibration curves for proteins in potassium phosphate buffers are shallower than those generated in sodium phosphate buffers. The slope of the curve in Sorenson buffer (containing both Na and ) is midway between the slopes generated with either cation alone (1). Table 4.4 illustrates the impact of different buffer conditions on mass recovery for six sample proteins. In this case, the mass recovery of proteins (1,4) is higher with sodium or potassium phosphate buffers (pH 6.9) than with Tris-HCl buffers (pH 7.8). 

FIGURE 10.8 A schematic diagram of the Na, K -ATPase in mammalian plasma membrane. ATP hydrolysis occurs on the cytoplasmic side of the membrane, Na ions are transported out of the cell, and ions are transported in. The transport stoichiometry is 3 Na out and 2 in per ATP hydrolyzed. The specific inhibitor ouabain (Figure 7.12) and other cardiac glycosides inhibit Na, K -ATPase by binding on the extracellular surface of the pump protein. 

FIGURE 10.13 Some of the sequence homologies in the nucleotide binding and phosphorylation domains of Na, K -ATPase, Ca -ATPase, and gastric H, K -ATPase. (Adapted from j0rgensm, P. L., and Andersen, J. R, 1988. Structnral basis for Ei - E2 confoyinational transitions in Na, K -pnmp and Cc -pnmp proteins. Journal of Membrane Biology 103 95-120)... 

The gradients of H, Na, and other cations and anions established by ATPases and other energy sources can be used for secondary active transport of various substrates. The best-understood systems use Na or gradients to transport amino acids and sugars in certain cells. Many of these systems operate as symports, with the ion and the transported amino acid or sugar moving in the same direction (that is, into the cell). In antiport processes, the ion and the other transported species move in opposite directions. (For example, the anion transporter of erythrocytes is an antiport.) Proton symport proteins are used by E. coU and other bacteria to accumulate lactose, arabinose, ribose, and a variety of amino acids. E. coli also possesses Na -symport systems for melibiose as well as for glutamate and other amino acids. 

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