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Beta-lactamase is a type of enzyme (EC 3.5.2.6) produced by some bacteria that is responsible for their resistance to beta-lactam antibiotics like penicillins, cephalosporins, cephamycins and carbapenems. These antibiotics have a common element in their molecular structure: a four-atom ring known as a beta-lactam. The lactamase enzyme breaks that ring open, deactivating the molecule's antibacterial properties.

Mediator of ErbB2-driven cell motility 1 (MEMO1) is a member of the UPF0103 family. MEMO1 regulates cell migration by transmitting extracellular chemotactic signals to the microtubule cytoskeleton. Furthermore, MEMO1 controls the localization of APC and CLASP2 to the cell membrane, using the regulation of GSK3B activity. MEMO1 is essential for breast carcinoma cell migration, suggesting a key role in tumorigenesis. MEMO1 is also a mediator of ERBB2 signaling.

Interleukin-1 receptor type 1 (IL1R1) associates with the co-receptor IL1RAP to form the high affinity interleukin-1 receptor complex, which mediates interleukin-1-dependent activation of NF-kappa-B, MAPK and other pathways. IL1R1 is a central mediator involved in numerous cytokine induced immune and inflammatory responses.

CD276, belongs to the B7 family of immunoregulatory transmembrane glycoproteins expressed by T cells. CD276 is a costimulatory molecule for T cell activation in addition to IFN-gamma production. Furthermore CD276 upregulates BRCC3 expression, preventing DNA defects caused by 5-Fu. CD276 is correlated with TNM stage of NSCLC and act as a potential biomarker for NSCLC-derived MPEs. CD276 inhibits natural-killer mediated cell lysis in tumor cells, and act as a marker for detection of neuroblastoma cells. CD276 is implicated in the development of acute as well as chronic transplant rejection and in the regulation of lymphocytic activity at mucosal surfaces. In addition, CD276 provides the placenta & fetus a proper immunological environment during the course of pregnancy.

CD38 is a surface molecule which acts as a plasma membrane signaling receptor in leukocytes. Furthermore, CD38 functions as signaling channel which leads to to cellular activation and proliferation. CD38 also plays a role as an ectoenzyme with various functions as well as an inducer of Ca2+ mobilization from cytoplasmic stores. CD38 signals acts as a coreceptor on B cells and modulates B cell receptor.

GST family of enzymes comprises a long list of cytosolic, mitochondrial, and microsomal proteins that are 45-55 kDa (dimer form) size and are capable of multiple reactions with a multitude of substrates, both endogenous and xenobiotic. GST catalyses the conjugation of reduced glutathione meaning the sulfhydryl group, to electrophilic centers on a wide variety of substrates. This activity is useful in the detoxification of endogenous compounds such as peroxidised lipids, as well as the metabolism of xenobiotics. GST binds toxins and function as transport protein. Glutathione S-transferase is used to create the so-called 'GST gene fusion system'. The GST is used to purify and detect proteins of interest. In a GST gene fusion system, the GST sequence is incorporated into an expression vector alongside the gene sequence encoding the protein of interest. Induction of protein expression from the vector's multiple cloning sites results in expression of a fusion protein - the protein of interest fused to the GST protein. This GST-fusion protein can then be purified from cells via its high affinity for glutathione. Fusion proteins offer an important biological assay for direct protein-to-protein interactions. The GST tag has the size of 220 amino acids, which, compared to other tags like the myc- or the FLAG-tag, is quite big. It is fused to the N-terminus of a protein. However, many commercially-available sources of GST-tagged plasmids include a thrombin domain for cleavage of the GST tag during protein purification. A GST-tag is often used to separate and purify proteins that contain the GST-fusion. GST-fusion proteins can be produced in Escherichia coli, as recombinant proteins.

Human papillomavirus family consist of over 200 types. Over than 30 to 40 types of HPV are transferred via sexual contact and infect the anogenital region initiating genital warts. Persistent infection with "high-risk" HPV types results in skin warts and leads to precancerous lesions and invasive cancer. HPV infection is considered as a source for all incidents of cervical cancer.

Chlamydia is a common term for infection with any bacterium belonging to the phylum Chlamydiae. This term derives from the name of the bacterial genus Chlamydiain the family Chlamydiaceae, order Chlamydiales, class and phylum Chlamydiae. There are two genera in Chlamydiaceae: Chlamydia and Chlamydophila. The genus Chlamydia includes three species: C. trachomatis, C. muridarum, and C. suis.

The HDV genome exists as a negative sense, single-stranded, closed circular RNA. Because of a nucleotide sequence that is 70% self-complementary, the HDV genome forms a partially double stranded RNA structure that is described as rod-like. With a genome of approximately 1700 nucleotides, It has been proposed that HDV may have originated from a class of plant viruses called viroids. Evidence in support of this hypothesis stems from the fact that both HDV and viroids exist as single-stranded, closed circular RNAs that have rod-like structures. Likewise, both HDV and viroids contain RNA sequences that can assume catalytically active structures called ribozymes.

Entry of HSV into the host cell involves interactions of several viral glycoproteins with cell surface receptors. The virus particle is covered by an envelope which, when bound to specific receptors on the cell surface, will fuse with the cell membrane and create an opening, or pore, through which the virus enters the host cell. The sequential stages of HSV entry are analagous to those of other viruses. At first, complementary receptors on the virus and cell surface bring the two membranes into proximity. In an intermediate state, the two membranes begin to merge, forming a hemifusion state. Finally, a stable entry pore is formed through which the viral envelope contents are introduced to the host cell.

Interleukin-8 (IL-8) is a chemokine produced by macrophages and other cell types such as epithelial cells. IL8 is also synthesized by endothelial cells, which store IL-8 in their storage vesicles, the Weibel-Palade bodies.When first encountering an antigen, the primary cells to encounter it are the macrophages who phagocytose the particle. Upon processing, they release chemokines to signal other immune cells to come in to the site of inflammation. IL-8 is one such chemokine. It serves as a chemical signal that attracts neutrophils at the site of inflammation, and therefore is also known as Neutrophil Chemotactic Factor.

Trichomonas vaginalis, an anaerobic, flagellated protozoan parasite, is most dominant protozoan causing sexual transmitted disease. T. vaginalis induced vaginal tract infection occurs as multiple steps involving interactions between host macromolecules and protozoan virulent factor. Adhension protein P65 of T. vaginalis has a vital part in assisting the penetration into vaginal tract surface.

HNMT is located in the cytosol and uses S-adenosyl-L-methionine as the methyl donor. In the mammal’s brain,N(tau)-methylation controls the neurotransmitter activity of histamine since diamine oxidase is not located in the central nervous system. A well known genetic polymorphism influences the activity levels of HNMT gene product in red blood cells. HNMT inactivates histamine by n-methylation. HNMT is involved in degrading histamine and in regulating the airway response to histamine. Histamine is involved in regulation and modulation of immune response through the stimulation of four distinct subtypes of receptors, H1, H2, H3, and H4, that present on the target cells. Histamine is inactivated by the histamine-metabolizing enzyme HNMT in bronchus, kidney, and the central nervous system.

a-Synuclein (amino acids 1-140), an acidic neuronal protein of 140 amino acids, is extremely heat-resistant and is natively unfolded with an extended structure primarily composed of random coils. a-synuclein has been suggested to be implicated in the pathogenesis of Parkinson’s disease and related neurodegenerative disorders, and more recently, to be an important regulatory component of vesicular transport in neuronal cells. Moreover, recent studies have shown that a-synuclein has chaperone activity and that this activity is lost upon removing its C-terminal acidic tail (amino acids 96-140).

H3N2 is a subtype of the influenza A virus. Its name derives from the forms of the two kinds of proteinson the surface of its coat, hemagglutinin(H) and neuraminidase(N). H3N2 exchanges genes for internal proteins with other influenza subtypes. H3N2 has tended to dominate in prevalence over H1N1, H1N2, and influenza B. H3N2 strain descended from H2N2 by antigenic shift, in which genes from multiple subtypes re-assorted to form a new virus. Both the H2N2and H3N2 strains contained genesfrom avian influenzaviruses.

Human immunodeficiency virus (HIV) is a retrovirusthat can lead to a condition in which the immune systembegins to fail, leading to opportunistic infections. HIV primarily infects vital cells in the humanimmune systemsuch as helper T cells(specifically CD4+ T cells), macrophagesand dendritic cells. HIV infection leads to low levels of CD4+ T cells through three main mechanisms: firstly, direct viral killing of infected cells; secondly, increased rates of apoptosisin infected cells; and thirdly, killing of infected CD4+ T cells by CD8 cytotoxic lymphocytesthat recognize infected cells. When CD4+ T cell numbers decline below a critical level, cell-mediated immunityis lost, and the body becomes progressively more susceptible to opportunistic infections. HIV was classified as a member of the genus Lentivirus, part of the family of Retroviridae. Lentiviruses have many common morphologies and biological properties. Many species are infected by lentiviruses, which are characteristically responsible for long-duration illnesses with a long incubation period. Lentiviruses are transmitted as single-stranded, positive-sense, enveloped RNA viruses. Upon entry of the target cell, the viral RNA genomeis converted to double-stranded DNAby a virally encoded reverse transcriptasethat is present in the virus particle. This viral DNA is then integrated into the cellular DNA by a virally encoded integraseso that the genome can be transcribed. Once the virus has infected the cell, two pathways are possible: either the virus becomes latentand the infected cell continues to function, or the virus becomes active and replicates, and a large number of virus particles are liberated that can then infect other cells.

Activins are homodimers or heterodimers of the different β subunit isoforms, part of the TGFβ family. Mature Activin A has two 116 amino acids residues βA subunits (βA-βA). Activin displays an extensive variety of biological activities, including mesoderm induction, neural cell differentiation, bone remodelling, haematopoiesis, and reproductive physiology. Activins takes part in the production and regulation of hormones such as FSH, LH, GnRH and ACTH. Cells that are identified to express Activin A include fibroblasts, endothelial cells, hepatocytes, vascular smooth muscle cells, macrophages, keratinocytes, osteoclasts, bone marrow monocytes, prostatic epithelium, neurons, chondrocytes, osteoblasts, Leydig cells, Sertoli cells, and ovarian granulosa cells.

Oncostatin M is a member of a cytokine family that includes leukemia-inhibitory factor, granulocyte colony-stimulating factor, and interleukin 6. This gene encodes a growth regulator which inhibits the proliferation of a number of tumor cell lines. It regulates cytokine production, including IL-6, G-CSF and GM-CSF from endothelial cells.

Interleukin-21 isoform 1 or IL21, categorized as a T helper cytokine. IL21 is part of the regulation of immune responses, haematopoiesis and cell-mediated responses. IL21 takes a main part in haematopoiesis and immune responses regulation, therefore can affect lymphocyte development. Activation of T cells leads to production of the IL21 which has an important role in the viral infections persistence.

Platelet endothelial cell adhesion molecule (PECAM1) induces susceptibility to atherosclerosis. PECAM1 averts phagocyte ingestion of closely apposed viable cells by transmitting detachment signals, and transforms function upon apoptosis, thus promoting tethering of dying cells to phagocytes. The encounter of a viable cell with a phagocyte via the homophilic interaction of PECAM1 on both cell surfaces as a result causing the viable cell's active repulsion from the phagocyte.

CD81 antigen isoform 1, also known as CD81, is part of the tetraspanin family. CD81 interacts directly with immunoglobulin superfamily member 8 (IGSF8, CD316) and CD36. In B cells, CD81 is part of a complex with CD21, CD19 and Leu13. Furthermore, this complex decreases the threshold for B cell activation through B cell receptors by linking Ag specific recognition and CD21 mediator recognition. While on T cells CD81 connects with CD4 and CD8 and provides a costimulatory signal with CD3.

MGMT is an enzyme that repairs O-6-methylguanine, a mutagenic DNA base damaged by endogenous and environmental alkylating agents and takes part in the cellular defense against the biological effects of O-6-methylguanine in DNA. MGMT repairs alkylated guanine in DNA by stoichiometrically transferring the alkyl group at the O-6 position to a cysteine residue in the enzyme. abnormal MGMT expression correlates with the prognosis in human solid cancers. MGMT decrease of expression is correlated with methylation. The human MGMT is a negative regulator of estrogen receptor-mediated transcription upon alkylation DNA damage. MGMT promoter hypermethylation plays an important role in the early steps of colorectal carcinogenesis. Abnormal promoter hypermethylation of MGMT gene is associated with oral squamous cell carcinomas.

Trypanosoma cruzi, better known as T. cruzi, is a deadly parasite that causes Chagas’ disease. This disease is a chronic infection, which primarily affects the heart and nervous system, causing severe neurological disorders, as well as swelling or denervation of nervous tissue in the heart, colon and esophagus. Chagas’ disease often goes undiagnosed due to close association of symptoms to heart disease and a variety of other disorders. The organism can circulate in the blood of infected patients for many years after infection, and can lead to transfusion-acquired infections in blood recipients from these infected donors. Contaminated blood transfusions are suspected to be the primary way in which the parasite has been transmitted to industrialized countries.

DCTD is an allosteric enzyme that exists as a homohexamer and is part of the cytidine and deoxycytidylate deaminase protein family. DTCD uses zinc as a cofactor to catalyze the deamination of dCMP to dUMP, thus making the nucleotide substrate (dUMP) that is used by thymidylate synthase.