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Treponema pallidum is a gram-negative spirochaete bacterium and is considered to be metabolically crippled. There are at least four known subspecies: T. pallidum pallidum, T. pallidum pertenue, T. pallidum carateum and T. pallidum endemicum. The helical structure of T. pallidum pallidum allows it to move in a corkscrew motion through viscous mediums such as mucus. Treponema pallidum sub sp. pallidum has one of the smallest bacterial genomes at 1.14 million base pairs (Mb) and has limited metabolic capabilities, reflecting its adaptation through genome reduction to the rich environment of mammalian tissue.

SARS Coronavirus is an enveloped virus containing three outer structural proteins, namely the membrane (M), envelope (E), and spike (S) proteins. Spike (S)-glycoprotein of the virus interacts with a cellular receptor and mediates membrane fusion to allow viral entry into susceptible target cells. Accordingly, S-protein plays an important role in virus infection cycle and is the primary target of neutralizing antibodies.

HCV is a small 50nm, enveloped, single-stranded, positive sense RNAvirus in the family Flaviviridae.
HCV has a high rate of replication with approximately one trillion particles produced each day in an infected individual. Due to lack of proofreading by the HCV RNA polymerase, the HCV has an exceptionally high mutation rate, a factor that may help it elude the host's immune response. Hepatitis C virus is classified into six genotypes(1-6) with several subtypes within each genotype. The preponderance and distribution of HCV genotypes varies globally. Genotype is clinically important in determining potential response to interferon-based therapy and the required duration of such therapy. Genotypes 1 and 4 are less responsive to interferon-based treatment than are the other genotypes (2, 3, 5 and 6).

Plasmodium falciparum is a protozoan parasite, one of the species of Plasmodium that cause malaria. Malaria parasites are members of the Apicomplexa. Apicomplexa are characterized by a set of organelles found in some stages of the parasite's life cycle. These organelles, collectively known as apical organelles because of their localization at one end of the parasite, are involved in interactions between the parasite and host. In particular, the apical organelles have been implicated in the process of host cell invasion. In the case of Plasmodium, three distinct invasive forms have been identified: sporozoite, merozoite, and ookinete.

CCAAT/enhancer binding protein(C/EBP) a is a family of transcription factors that all contain a highly conserved, basic-leucine zipper domain at the C-terminus that is involved in dimerization and DNA binding. C/EBP family of transcription factors regulates viral and cellular CCAAT/enhancer element-mediated transcription. C/EBP family consist of several related proteins, C/EBP a,b,g,d, that form homodimers and that form heterodimers with each other. C/EBP proteins contain the bZIP region, which is characterized by two motifs in the C-terminal half of the protein; a basic region involved in DNA binding and a leucine zipper motif involved in dimerization. C/EBPs differ significantly in their physiological functions and in their downstream target genes. For example, mice lacking C/EBPa die shortly after birth due to severe hypoglycemia and the absence of glycogen storage in liver, whereas knockout of C/EBPb causes defects in female reproduction.

SARS Coronavirus is an enveloped virus containing three outer structural proteins, namely the membrane (M), envelope (E), and spike (S) proteins. Spike (S)-glycoprotein of the virus interacts with a cellular receptor and mediates membrane fusion to allow viral entry into susceptible target cells. Accordingly, S-protein plays an important role in virus infection cycle and is the primary target of neutralizing antibodies.

HCV is a small 50nm, enveloped, single-stranded, positive sense RNAvirus in the family Flaviviridae. HCV has a high rate of replication with approximately one trillion particles produced each day in an infected individual. Due to lack of proofreading by the HCV RNA polymerase, the HCV has an exceptionally high mutation rate, a factor that may help it elude the host's immune response. Hepatitis C virus is classified into six genotypes(1-6) with several subtypes within each genotype. The preponderance and distribution of HCV genotypes varies globally. Genotype is clinically important in determining potential response to interferon-based therapy and the required duration of such therapy. Genotypes 1 and 4 are less responsive to interferon-based treatment than are the other genotypes (2, 3, 5 and 6). HCV NS3 (genotype 1b) contains 2 domains which are serine protinase and helicase. C33c is a fragment of NS3 containing the most important epitopes recognized by HCV antibody.

Smac/Diablo is a proapoptotic protein that increases caspase activation in the cytochrome c/Apaf-1/caspase-9 pathway by its binding to the inhibitor of apoptosis proteins (IAPs) and removing their inhibitory activity. Smac/Diablo is a mitochondrial protein which enters the cytosol when cells go through apoptosis, and it moderates the caspase inhibition of IAPs.
Smac/DIABLO expression is associated with the result of renal cell carcinoma.
Dimeric form of Smac/DIABLO implies that once expressed in the cell the protein has a little probability of dissociation and, thus, loss of function.
Survivin, Smac/DIABLO, & PKC-? play an important part in the inhibition of apoptosis by FGF-2 in human small cell lung cancer cells. Mitochondrial survivin associates with Smac/DIABLO, delaying its release. Decreased expression of Smac protein takes part in ovarian carcinogenesis and chemotherapeutic resistance. Smac/DIABLO plays a role in tumor cells during the pathway of apoptosis induction. SMAC protein is regulated by XIAP and degraded by proteasome. SMAC protein takes part inleukemic cell apoptosis.
Smac is released during stress-induced apoptosis in multiple myeloma cells.

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).

Tumor necrosis factor is a cytokine involved in systemic inflammation and is a member of a group of cytokines that all stimulate the acute phase reaction. TNF is mainly secreted by macrophages.
TNF causes apoptotic cell death, cellular proliferation, differentiation, inflammation, tumorigenesis and viral replication, TNF is also involved in lipid metabolism, and coagulation. TNF's primary role is in the regulation of immune cells.
Dysregulation and, in particular, overproduction of TNF have been implicated in a variety of human diseases- autoimmune diseases, insulin resistance, and cancer.

A human infecting coronavirus (viral pneumonia) called 2019 novel coronavirus, 2019-nCoV was found in the fish market at the city of Wuhan, Hubei province of China on December 2019.
The 2019-nCoV shares an 87% identity to the 2 bat-derived severe acute respiratory syndrome 2018 SARS-CoV-2 located in Zhoushan of eastern China. 2019-nCoV has an analogous receptor-BD-structure to that of 2018 SARS-CoV, even though there is a.a. diversity so thus the 2019-nCoV might bind to ACE2 receptor protein (angiotensin-converting enzyme 2) in humans.
On November 2021, WHO designated a variant of concern, named Omicron. Omicron has several mutations that may have an impact on how it behaves (how easily it spreads, the severity of illness).

SPON1 is a cell adhesion protein which take part in the regulation of protein binding activity, regulation of protein processing and regulation of amyloid precursor protein catabolic mechanism. SPON1 is found in the extracellular space and it co-localizes with collagen-containing extracellular matrix. SPON1 stimulates the attachment of spinal cord and sensory neuron cells and the outgrowth of neurites in vitro.

Since April 2012, cases of the Middle East Respiratory Syndrome Coronavirus (MERS-CoV) have been identified in various countries. Coronaviruses are the cause of the common cold, SARS (severe acute respiratory syndrome) and other severe illnesses with high mortality rates, all are classified into coronavirus family. MERS-CoV is a new type of SARS found in the coronavirus family causing severe pneumonia with sudden and serious respiratory illness with high mortality rates as well. Since January 27th 2015, the WHO has reported 956 human cases, including 351 deaths. More cases of the new coronavirus strain are expected. Like in other coronaviruses, large surface spike glycoprotein is a central structural protein of this virus; it is located above the virion surface to bind and enter into the target cell. Spike protein has 2 domains- S1 and S2. The S1 domain is responsible for cellular tropism and interaction with target cell, while the S2 domain is responsible for membrane fusion. The C-terminal of S1 domain contains a receptor binding domain, and is also a potential target for vaccine development and an antigen for diagnosis.

A 16-kDa peptide hormone secreted from white adipocytes and implicated in the regulation of food intake and energy balance. Leptin provides the key afferent signal from fat cells in the feedback system that controls body fat stores.

IGFBP1 is a member of the insulin-like growth factor binding protein (IGFBP) family and encodes a protein with an IGFBP domain and a thyroglobulin type-I domain. The protein binds both insulin-like growth factors (IGFs) I and II and circulates in the plasma. Binding of this protein prolongs the half-life of the IGFs and alters their interaction with cell surface receptors. Alternate transcriptional splice variants, encoding different isoforms, have been characterized.

C3 is central to the activation of all 3 pathways of complement activation. Initiation of each pathway generates proteolytic enzyme complexes which binds the target surface. These enzymes cleave a peptide bond in C3 releasing the anaphylatoxin C3a and activating C3b. Most of the C3 activated during complement activation never attaches to the surface due to its thioester reaction with water forming fluid phase C3b which is rapidly inactivated by factors H and I forming iC3b. Surface-bound C3b is necessary in all 3 pathways for efficient activation of C5 and formation of C5b-9 complexes that lyse the target cell membrane.

TARC cDNA encodes a 94 amino acid precursor protein with a 23 amino acid residue signal peptide that is cleaved off to generate the 71 amino acid residue mature secreted protein. Along with CC chemokine family members, CCL-17 has approximately 24-29% amino acid sequence identity with RANTES, MIP-1a, MIP-1b, MCP-1, MCP-2, MCP-3 and I-309. TARC is expressed in thymus, and at a lower level in the lung, colon, and small intestine. TARC is in addition transiently expressed in stimulated peripheral blood mononuclear cells. Recombinant TARC has been shown to be chemotactic for T cell lines but not monocytes or neutrophils. CCL-17 is a specific functional ligand for CCR4, a receptor that is selectively expressed on T cells. CCL17 is one of a few Cys-Cys (CC) cytokine genes clustered on the q arm of chromosome 16. CCL17 shows chemotactic activity for T lymphocytes, but not monocytes or granulocytes. CCL17 binds to chemokine receptors CCR4 and CCR8. This chemokine plays important roles in T cell development in thymus as well as in trafficking and activation of mature T cells.

SARS Coronavirus is an enveloped virus containing three outer structural proteins, namely the membrane (M), envelope (E), and spike (S) proteins. Spike (S)-glycoprotein of the virus interacts with a cellular receptor and mediates membrane fusion to allow viral entry into susceptible target cells. Accordingly, S-protein plays an important role in virus infection cycle and is the primary target of neutralizing antibodies.

15 KDa Selenoprotein (SEP15) is a protein-coding gene which contains a selenocysteine (Sec) residue at its active site. Theselenocysteine is encoded by the UGA codon that usually signals translation termination. The 3' UTR ofselenoprotein genes have a conventional stem-loop structure, the sec insertion sequence (SECIS), which isnecessary for the recognition of UGA as a Sec codon rather than as a stop signal. Studies in mouse propose thatthis selenoprotein may have redox function and may be implicated in the quality control of protein folding. This geneis localized on chromosome 1p31, a genetic locus usually mutated or deleted in human cancers.Diseases associated with SEP15 include lung cancer susceptibility, and chronic lymphocytic leukemia.

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).

PPIF is a part of the peptidyl-prolyl cis-trans isomerase (PPIase) family. PPIF accelerates the folding of proteins. It catalyzes the cis-trans isomerization of proline imidic peptide bonds in oligopeptides. PPIF is key component of the mitochondrial permeability transition pore in the inner mitochondrial membrane. Activation of this pore is thought to be involved in the induction of apoptotic and necrotic cell death.

Biglycan (BGN) is a small cellular or pericellular matrix proteoglycan which takes part in assembly of collagen fibrils and muscle regeneration. BGN is closely correlated in structure to two other small proteoglycans, decorin and fibromodulin. BGN interacts with several proteins involved in muscular dystrophy, including alpha-dystroglycan, alpha- and gamma-sarcoglycan and collagen VI. BGN is also critical for the assembly of the dystrophin-associated protein complex.

The La protein is a 47 kDa polypeptide that frequently acts as an autoantigen in systemic lupus erythematosus and Sjogren's syndrome patients. La is involved in various aspects of RNA metabolism, including binding and protecting 3-prime UUU(OH) elements of newly RNA polymerase III - transcribed RNA, processing 5-prime and 3-prime ends of pre-tRNA precursors, acting as an RNA chaperone, and binding viral RNAs linked to hepatitis C virus. It occurs in both the nucleus and the cytoplasm, where it assumes different roles. In the nucleus, La protein facilitates the production of tRNAs, acting as an RNA polymerase III (RNAP III) transcription factor by attaching to the U-rich 3'UTR of nascent transcripts, aiding in their folding and maturation. In the cytoplasm, La protein facilitates the translation of specific mRNAs, acting as a translation factor. As an RNA binding protein (RBP), La protein associates with subsets of mRNAs which contain a 5'-terminal oligopyrimidine (5'TOP) motif known to direct protein synthesis. The binding of La protein to particular classes of RNA molecules regulates their downstream processing, guards them from endonuclease digestion, and organizes their export from the nucleus. La/SS-B appears to be readily disposed to proteolysis, which results in many smaller (42kD, 320, and 270) nevertheless still immunoreactive polypeptides. La/SS-B antigen is strongly conserved across species. Anti-La/SS-B autoantibodies were originally found as precipitating autoantibodies in sera of Sjogren's Syndrome patients and referred to as SjT. Anti-La/SS-B precipitins are most frequently found in Sjogren's Syndrome, Systemic Lupus Erythematosus (SLE) and Subacute Cutaneous Lupus. Also, there seems to be a correlation between anti-La/SS-B and the absence of nephritis in SLE patients.