Protein performance

Membrane proteins comprise another important class of protein crystallized in 2D. These proteins perform important functions as membrane channels and recognition sites for cells. Unlike the streptavidin crystals, membrane proteins... 

Ancillary to the proteins performing these functions are others which transport and store the iron itself. All these proteins are conveniently categorized according to whether or not they contain haem, and the more important classes found in nature are listed in Table 25.7. 

Most of the stress proteins discussed in this account have a role either in helping the plants survive, or in minimising the effectiveness of the stress agent. In helping plants survive under stress conditions, the stress proteins perform the following functions (1) maintenance of the basic metabolism in the stressed cell, e.g. the induction of ADH and some... 

Proteins may be classified on the basis of the solubility, shape, or function or of the presence of a prosthetic group such as heme. Proteins perform complex physical and catalytic functions by positioning specific chemical groups in a precise three-dimensional arrangement that is both functionally efficient and physically strong. 

The other major class of extracellular LBPs of mammals is the lipocalins (Flower, 1996). These are approximately 20 kDa, P-sheet-rich proteins, performing functions such as the transport of retinol in plasma or milk, the capture of odorants in olfaction, invertebrate coloration, dispersal of pheromones, and solubilizing the lipids in tears (Flower, 1996). The retinol-binding protein (RBP) of human plasma is found in association with a larger protein, transthyretin, the complex being larger than the kidney threshold and thus not excreted, although the RBP itself may dissociate from the complex to interact with cell surface receptors in the delivery of retinol (Papiz et al., 1986 Sundaram et al., 1998). 

The O-ECAT reagent is a superior alternative to the use of 2,4-dinitrophenylhydrazine (DNPH Chapter 1, Section 1.1) in the study of protein oxidation. DNPH modification produces detectable complexes, but it does not provide information as to what amino acids are involved. O-ECAT modifies carbonyl end products of protein oxidation and in addition, it can provide exact information as to the amino acids that were oxidized. Mass spec analysis of modified proteins performed after proteolysis gives the exact amino acid sequences including the sites of O-ECAT reagent modification. The same antibody that is specific for the metal chelate portion of the standard ECAT reagent also can be used to capture and detect the O-ECAT... 

In addition, there are a number of borderline cases, whose sequence relationship to ubiquitin is hard to establish but most probably is real, as these proteins perform a similar function. One well-known example is the UBX domain [44, 45], which seems to replace an internal ubiquitin domain in a certain class of adapter proteins (see Section 12.5.2). Other examples are the autophagy proteins Apg8 and Apgl2 [23, 24] which act as ubiquitin-like modifiers. 

As shown in Table V, a number of Fe S-containing proteins perform reactions other than redox or electron transfer. That is, the function of the cluster does not include a change in oxidation state, even as a transient step in catalysis. This role is best illustrated by aconitase, one of the most extensively studied Fe S proteins, regardless of function. The elegant recent work on this enzyme is largely under the guiding hand of H. Beinert and is summarized in the Krebs Memorial Lecture (Beinert and Kennedy, 1989). 

Fig. 9.2. The GTPase cycle of the Ras protein. Conversion of the inactive Ras GDP complex into the active Ras GTP complex is brought about by guanine nucleotide exchange factors (GEFs). The activated state of the Ras protein is terminated by hydrolysis of the bound GTP. The help of a GTPase actvating protein (GAP) is required, due to the intrinsically slow GTPase activity of the Ras protein. Ras protein performs all its functions in close association with the cell membrane. It carries a membrane anchor and the effector proteins preceding and following in sequence are also associated with the membrane.

I am not familiar with the results you mentioned. Looking for the biochemical studies that have directly confirmed our observation of molecular tunneling in chemical reactions, one should mention the investigations of the dynamics of ligand rebinding to heme proteins performed by H. Frauenfelder, I. Gunsalus, and their colleagues at the University of Illinois (Urbana, 111.) [see, e.g., Biochemistry, 14, 5355 (1975) and Science, 192, 1002 (1976)]. 

E Tatar, M Khalifa, G Zaray, I Molnar-Perl. Comparison of the recovery of amino acids in vapor-phase hydrolysates of proteins performed in a Pico Tag work station and in a microwave hydrolysis system. J Chromatogr A 672 109-115, 1994. 

The chalcone synthase (CHS) (EC 2.3.1.74) superfamily of type III Polyketide synthases (PKSs) are pivotal enzymes in the biosynthesis of plant polyphenols. They are structurally and mechanistically different from the modular type I and the dissociated type II PKSs of bacterial origin the simple homodimer of 4CM-5 kDa proteins performs a complete series of decarboxylation, condensation, cyclization,... 

Translation The process of copying mRNA into protein performed by ribosomal RNA. 

May indicate non-specific binding of the primary antibody carrier-protein. Perform a protein block with normal serum from the host of the link antibody add 0.05-0.1% TWEEN 20 to wash buffer to decrease protein attachment. 

FIGURE 8 Separation of rabbit polyclonal antibodies by ion-exchange chromatography on DEAE Trisacryl M. Column dimensions 16 mm i.d.X 100 mm initial buffer 50 mM Tris-HCI, 0.035 M sodium chloride, pH 8.8 load 5 mL of rabbit serum previously precipitated with ammonium sulfate at 50% saturation and redissolved in column buffer flow rate 50 mL/hr elution of adsorbed protein performed using I M sodium chloride solution in the initial Tris buffer. The first peak represents IgG the second peak is composed of all other serum proteins precipitated by ammonium sulfate. The straight line is absorbance at 280 nm, and the broken line represents the variation of ionic strength of the buffer. The purity of IgG estimated by gel electrophoresis was over 98% and the calculated yield was over 90%. 

The third ABC protein believed to play a role in clinical MDR, ABCG2 (MXR/BCRP) is a half transporter [15,34], with a unique domain arrangement, where the ABC is located at the N-lerminus (Fig. 2). This protein performs an active extrusion of hydrophobic, positively charged molecules... 

Zinc complexes in proteins perform structural, catalytic, and regulatory functions. Structural zinc sites typically adopt tetrahedral or distorted tetrahedral coordination geometries formed by four protein-derived ligands with no bound water molecules. Cysteines and histidines are by far the preferred ligands in such sites (e.g. zinc fingers see Section 2). ... 

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