Topology of the Membrane-Bound

Molecular Cell Biology, 7th Edition, 2013, Lodish, Berk, Kaiser, Krieger, Bretscher. Ploegh, Amon, and Scott. W.H. Freeman and Company (ISBN-13: 978-1-4292-3413-9)

Cell wall of bacteria contains rigid and complex structure which maintains the cytoplasm of cell gives structural integrity and prevents osmotic lysis. Both Garm positive and Gram negative bacteria contain a carbohydrate complex structure called Peptidoglycan also called Muerin. The layer is thicker in Gram positive bacteria whereas in Gram negative bacteria the peptidoglyacan layer is thinner; moreover this is protected by an outer membrane layer called Lipopolysaccharide (LPS). The Peptidoglycan consists of two monomers called N-Acetylglucosamine(NAG) and N-Acetylmuramic acid(NAM). These two carbohydrate containing monomers are linked by glycosidic linkages. A pentapeptide bond attaches to NAM which gives crosslinkage and rigidity to the layer.

Complement proteins are a group of about 20 proteins that “complement” defense reactions. These proteins help attract phagocytes to foreign cells and help destroy foreign cells by promoting cell lysis (breaking open the cell).

Collagen IV, the primary constituent of the basement membrane provides stability and structural integrity to epithelial and vascular tissues. Additionally, collagen IV plays a vital role in cell signaling and can be influential in the progression of certain auto immune diseases. Structurally collagen IV is an oligomer of triple helical protomers that are covalently crosslinked by the means of sulfilimine bonds. The bond itself has been evolutionarily conserved and has direct contributions to tissue development as well as autoimmune disease. Given these developments the goal of the research that contributed to this paper was to find the molecular mechanism by which sulfilimine bonds were formed.

It is action is mediated by Protein Kinase G (PKG) , a cGMP-dependent protein kinase, that phosphorylates target proteins in the cell.

All integrins are composed of two linked polypeptide chains, α and β. The β2 integrins are called CD11/CD18 where CD11 refers to the α chain and CD18 refers to the β2 subunit (Kumar et al, 2005). CD11/CD18 play a primary roll in adhesion of leukocytes to other cells which mediates leukocyte attachment and extravasation or transmigration.

The size of syndecans varies between 20 to 45 kDa depending on the syndecan’s type3. They are linked to the cellular cytoskeleton6. Therefore, they regulate the organization of cytoskeleton and actin microfilaments. They also play a role in endocytosis and the regulation of cell surface receptors during cell-cell and cell-matrix interactions7. In addition, syndecan molecule consists of four domains; a single sequence, extracellular domain that has sites for the attachment of heparin sulfate glycosaminoglycan side chains, a transmembrane region and short, highly conservative cytoplasmic domain of about 30 to 35 residues that helps in the interaction of syndecan molecules with cytoskeletal proteins5. The cytoplasmic region consists of two conserved regions; C1 (which is proximal to the plasma membrane) and C2 (which is distal to plasma membrane). A variable region is located between C1 and C2 regions3. Moreover, the extracellular domain is specific for each type of syndecan. It binds to 3 to 5 chains of HS or CS3. Syndecan-2 and 4 bind to HS while Syndecan-1 and 3 bind to CS in addition of HS3. The most prominent member of the syndecan family in the vasculature is syndecan-23. Moreover, Shedding of the extracellular of Syndecan occurs in response to complement activation8, endotoxin9, growth factors and thrombin10, serine and/or cystein proteinases11,

Kinesin heavy chain is my target protein. It has 975 amino acids. Drosophilia Melanogaster is the organism. A kinesin is a protein belonging to a class of motor proteins found in eukaryotic cells. Kinesins move along microtubule filaments, and are powered by the hydrolysis of ATP. The active movement of kinesins supports several cellular functions including mitosis, meiosis and transport of cellular cargo, such as in axonal transport. Most kinesins walk towards the positive end of a microtubule, which, in most cells, entails transporting cargo such as protein and membrane components from the center of the cell towards the periphery. In contrast, dyneins are motor proteins that move toward the microtubules' negative end.

The de-ubiquitinase (DUB) will cleave this precursor into free monomer ubiquitin molecules and can be activated and attached to the target protein through ATP dependent process called ubiquitination with the help of activating enzyme E1, conjugating enzyme E2, and ligase E3. Through forming (iso)-peptide, thioester, or ester bond between carboxyl groups of C-terminal glycine 76 on ubiquitin and the ε-amino group of the lysine, cysteine, serine/threonine on the substrate, respectively, the poly-ubiquitin chain is formed [3]. Based on the different internal Lysine (Lys6, Lys11, Lys27, Lys29, Lys33, Lys48, and Lys63) and on the proximal ubiquitin, the (iso)-peptide bond can be form with another ubiquitin, distal mono-ubiquitin [4, 5]. Consequently, seven conventional poly-ubiquitin chains resulting in different 3-dimentional shapes explaining its different characteristics inherited upon binding to the target protein [5, 6]. With ranging more than 500 putative E3 ligases exist in human, the E3 ligase will tag the poly-ubiquitin chain to the target protein with high specificity

using 50 µg of the same antigen emulsified in Freund's incomplete adjuvant (Sigma) at 14-day intervals. Sera were collected 2 weeks after the last booster and checked for specific antibodies by an indirect immunofluorescence assay (IFA). 2.6. SDS-PAGE and Western blotting Proteins in the extracts were size-separated under reducing conditions by

CRC is one of the most common cancers. Yet, its etiology and biology are not completely understood. In his study of 2013, mass spectrometry has been used to characterize glycans. Multivariate data analysis has showed consistent differences between CRC tumor tissues and control tissues. Some

Proteins are essential for cellular functions in all forms of life. Though proteins have been studied for decades, membrane proteins have not been properly understood due in part to their physical complexity and the difficulties in testing. Though many challenges hinder the discoveries in this area of biochemistry, Professor Alessandro Senes believes that the difficulties encountered only make the results more worthwhile. Researching these proteins advances our understanding of the importance of the protein structure on the molecular function in the cells. As Professor Senes and his team continue to explore recurring patterns in these membrane proteins, they further explore new topics in this growing area of science.

The PP is an aqueous cellular compartment delimited by the OM and IM, characterized by being densely packed with proteins and more viscous than the cytoplasm. Other proteins located in this compartment include periplasmic binding proteins and chaperon-like molecules required in the envelope biogenesis process. The PG layer contained within the PP is made up of repetitive units of the N-acetyl glucosamine-N-acetyl muramic acid, cross-linked by the penta-peptide side chain, and its importance resides in that it determines the cell

According to their previous research, a “repebody” is nonantibody protein structure containing consensus designed leucine rich repeat modules.2 This particular protein was recently discovered in

The plasma membrane is made up of four components. The first component is the phospholipid bilayer that consist of a hydrophilic head and a hydrophobic tail. Its function is to “help give the membrane its fluid nature” (). Also it helps the membrane to control what enters and exits cells. Cholesterol is another component whose function is to “act as a kind of patching substance on the bilayer, keeping some small molecules from getting through” (). Furthermore, cholesterol help to keep the membrane at an optimum level of fluidity. Next is protein which provides a huge array of capabilities. Proteins functions includes providing structural support in cells, it help the immune system to identify the cells as normal or infected, aids in the transport of material in and out of cells, and proteins also serves as receptors for certain molecules. The fourth component is the glycocalyx its function is to serve as a