Taking a Look at Surfactant Protein-D

Data from previous studies suggest that the inactive sHSP takes on the oligomer conformation Upon stress, these oligomers assemble into active dimeric species, exposing previously inaccessible hydrophobic surfaces that can then interact with nonpolar patches on the misfolded substrate, capturing them in large complexes. The sHSP-substrate complexes maintain the substrate in a folding-competent state for extended periods of time. Biologically this is of utmost importance since it is

Second, in order to further confirm the information about characteristics and function of the targeting protein that we have

The next two molecules, α6β4 integrin, and collagen XVII extend beyond the basal keratinocyte membrane and into the lamina lucida layer of the basement membrane zone and hence they are known as transmembrane molecules. These latter two molecules can be found within the outer plaque of the hemidesmosome. The last molecule, CD151, the most recently discovered molecule, is closely associated with α6β4 Integrin, and resides at or near the surface of the basal cell plasma membrane. The intermediate filaments attach to BPAG1 and plectin, which compose the hemidesmosome inner plaque. Both plectin and BPAG1 belong to the plakin family of proteins, and share significant sequence homology.[14]

The dexamethasone binding pocket of GR LBD consists of 3, 4, 5, 6, 7 and 10 helices as well as AF-2 helix. Within the crystals, dexamethasone shows a high affinity binding to the protein binding pocket [7, 1]. This high affinity binding is explained by the ability of dexamethasone to form both hydrophobic as well as hydrophilic interactions. Each atom of dexamethasone interacts with at least one of the hydrophobic residues from the GR LBD binding core. The hydrophilic interactions is formed by hydrogen bonds between the hydrophilic groups

A protein’s tertiary structure, the compact, biologically active and most stable form of the protein, results from further folding of the amino acid chain. The environment in which a protein is synthesized and allowed to folded is a significant determinant of its final shape. If the tertiary structure of a protein is disrupted, the protein is said to be denatured, and it loses its activity. Based on their tertiary structure, proteins can be classified as globular, fibrous and membrane proteins. Globular proteins participate in sophisticated processes such as enzyme-mediated catalysis, transport of molecules, signal transduction, defense and regulation.

Hydrophobic interactions, the weakest of the 4 bonds, occurs between nonpolar amino acids. These amino acids are not capable of hydrogen bonding or forming charge to charge interactions. The hydrophobic parts are kept on the inside of the watery environment of the cell pulling the protein into a tightly folded shape.

Tachylectin-5A is an ellipsoidal molecule that is an asymmetrical monomer, which is subdivided into three different domains that interact with each other (2). The primary structure of Tachylectin-5A constitutes 269 amino acid residues (1). The amino acid composition of this protein has a cis-peptide bone between Arg-218 and Cys-219 (3). It contains one protein modification called prryolidone carboxylic acid, which is the twenty-fourth amino acid in the sequence (1). And the secondary structure of the protein consists of 16% alpha helical and 24% beta sheets. There are 9 helices with 44 amino acid residues and 19 beta sheets with 66 residues involved in total (1). The

Two of the main functions of galectin-8 are cell adhesion and cell growth. These functions also occur in the protease-resistant form of galectin-8. Galectin-8 is a type of protein that is secreted. When it is secreted, is serves a modulator for cell adhesion [3]. When the protein is stopped, it promotes cell adhesion. This occurs by ligation and gathering of a select group of integrin receptors [3]. Recall that galectin-8 is a sugar binding protein. Therefore, when there is a formation between galectin-8 and integrins, it activates integrin-mediated signaling [3]. When there are large amounts of galectin-8 present, it negative regulates cell adhesion with it forms a complex with integrins. Cell adhesion depends on the interactions between galectin-8

Proteins with his-tags are purified using IMAC, immobilized metal affinity chromatography. The protein product interacts with a metal that is reversibly bound to an immobilized chelating group. The immobolized chelating group acts as a Lewis base (electron-pair donor) to which the Lewis acid (electron-pair acceptor) metal ion is coordinated. The support to which the metal ion binds is called a ligand. When an electron donor group is replaced by another, the action is referred to as ligand exchange. The donor atoms involved in this exchange are the electronegative nitrogen, sulfur, or oxygen. These atoms scavenge for sources of electrons. The structure formed when the metal ions are added to form the chelate result in free coordination

CD 36 is a type of integrin protein, which is found mostly in the human. It usually binds to collagen, thrombospondin, anionic phospholipids and more. They are also glycosylated, and are an integrin plasma membrane protein that vary in a family that bind to lipid receptors. It functions in recognizing different lipoproteins, fatty acid transports, and cell – matrix interactions. This integrin is very diverse and deals mostly with fatty acid structures.

Albumin, a 66.5 kDa protein, is quantitatively the most important plasma protein [85]. Albumin is the main determinant of plasma oncotic pressure, it plays a pivotal role in modulating the distribution of fluids between compartments, and exhibits many other biological functions, such as transport of endogenous and exogenous compounds, modulation of capillary permeability, neutrophil adhesion and activation, hemostasis and free radical scavenging (for review see 86]. Even mild oxidation of human serum albumin (HAS) impairs HSA functional properties including protease susceptibility, ligand-binding affinity and antioxidant activity [87]. The major structural change in oxidized HSA is a disulfide-bonded cysteine at the thiol of Cys34 of reduced HAS

In this investigation, experiments were conducted to determine the protein-protein interactions between GST, GST-EBNA1 and 6xHis USP7 through affinity chromatography, overexpression and SDS PAGE analysis. The hypothesis states that the EBNA1 would interact with 6xHis USP7, whereas the GST peptide would not be able to bind to 6xHis USP7. The results of the experiments performed mostly supported the hypothesis, and are further discussed in this section.

Phospholipase D (PLD) is a key enzyme for the production of phosphatidic acid, a lipid second messenger. Phosphatidic acid involves in both G protein-coupled receptor and receptor tyrosine kinase signal transduction networks.

The P-type lectins, CD-MPR and CI-MPR, are among the most extensively characterized lectins in the secretory pathway (for reviews see [110-112]). Comprising the only two members of this family, MPRs are defined by their unique ability to bind phosphomannosyl residues. The only known function of the CD-MPR is targeting newly synthesized acid hydrolases to the lysosome, whereas the CI-MPR is a multifunctional protein that interacts with several different ligands, including M6P-tagged acid hydrolases as well as the non-M6P-containing proteins insulin-like growth factor 2 (IGF-2) [113, 114], plasminogen [115, 116], and urokinase-type plasminogen activator receptor [117, 118]. Transgenic mice lacking the CD-MPR are viable [119]. Mice lacking

The interactions between A1-40 and nanodiscs was studied using ITC measurements. In reference to our CD results which showed a typical sheet conformation in A1-40 in both zwitterionic and anionic nanodiscs, we measured the binding affinity (Kd) of A1-40 in DMPC (100%) and DMPC mixed with variable percentage of anionic lipids such as DMPG and cardiolipin (CL). A1-40 was observed to induce an intermediate -helix conformation in the presence of anionic lipids such as GM1 and phosphatidylserine and phosphatidylglycerol. Thus, we targeted anionic lipids to examine how the membrane compositions in nanodiscs affect the binding kinetics. As shown in Fig 2b, distinct therograms were obtained for A1-40 (20 M) in the targeted nanodiscs (400 M lipids) containing 85 M PMA. A recent study showed that A1-40 doesn’t bind to zwitterionic membranes using fluorescence titrations [35]. On the other hand, studies have shown that different sizes of zwitterionic liposomes (DPOC and POPC) accelerate A1-40 aggregation significantly at micro-molar concentration [19]. Moreover, we showed in a recent study that zwitterionic lipids such as DLPC accelerates A1-40 aggregation at very low concentrations and also inhibits and remodel fibrillation [33]. Structural studies using NMR and computational methods also