Cardiovascular diseases (CVD) are the leading to of death throughout the world. The world health organization (WHO) world health report 2006 reported that 18 million people die from CVD every year. Intravascular thrombosis due to fibrin aggregation in arteries is anmain cause of CVD. Fibrin is the primary protein component of blood clots. Which are formed from fibrinogen by thrombin (D.voet&voet). The insoluble fibrin fibre is hydrolyzed into fibrin degradation product by plasminogen activators such as tissue plasminogen activator (t PA), urokinase and factor XII .In this researchwe consider to analyzed the sequence of (t PA), urokinase and factor XII in order to identify conserved sequence regions and possible similarities and differences and compare relationship between of biological functions and structures. In this regard the sequences of tissue plasminogen activator were extracted from uniport KB/ swissport and entries in FASTA format and the data were analyzed by FASTA protein program. Results revealed that the tissue plasminogen activator sequence 96% similar to urokinase-type plasminogen activator and 59% similar to coagulation factor XII that all of them contribute to fibrinolytic activity.

Antimicrobial peptides are a significance and varied group of peptides that are secreted by different tissues and cells in a wide variety of invertebrate, plant and animal species with widespread potency such as antibacterial, viral, fungal, parasitic, protist, cancer and antioxidant activities. Different BIOINFORMATICs approaches have been done for finding any reliable parameters between antimicrobial activities and their physicochemical properties. Analyzing about 2500 antimicrobial peptides show that more than 80% of antimicrobial peptides have antibacterial activity and only less than 6% are antiviral. It seems the disulfide bonds play an important role in antiviral activity because of having the highest disulfide population in antiviral peptides (~25%) in comparing the population in antibacterial (~10%) and antifungal peptides (~14%). The average length of antimicrobial peptides is 32.38 residues with average net charge of +3.19. It indicates that the basic charged residues including His, Lys and Arg dominated to acidic residues. Therefore most of antimicrobial peptides have basic properties. Also, the smallest residue of Gly participate more than 11% that resulted in highly flexible state of the antimicrobial peptides in solution. The least amount of residues in antimicrobial peptides population are Met and Trp with average compositions of 1.24%, 1.55% respectively. Moreover structural analysis indicates that the secondary helix conformation is dominated to beta strand and/or other combined structures in the antimicrobial peptides.

Background: Staphylococcus aureus and Staphylococcus epidermidis are major human pathogens of increasing importance due to the spread of antibiotic resistance. Novel potential targets for therapeutic antibodies are products of staphylococcal genes expressed during human infection. Previously, the secreted and surface-exposed proteins among seroreactive antigens have been discovered. Furthermore, approximately 60 immunogenic proteins were identified and have shown that bacterial surface display is uniquely suited to assess the value of the antigenic epitope. Methods: Using a BIOINFORMATIC analysis, a novel gene family was identified in Staphylococcus aureus and S. epidermidis. NCBI (National Center for Biotechnology Information) BLAST and TIGR search were used for identification of the loci on Staphylococcal genomes.Results: The members of nine gene family from S. aureus based on a conserved Cterminal domain following an N-terminal domain which varies in sequence and length.Further Blast P searches for paralogues revealed the novel Sca gene family in S.epidermidis has also highly conserved 110 amino acid C-terminal domain. Thus the Sca family has a conserved domain across different genera. Conclusion: Further studies to determine the role of the conserved Sca domain in ligand binding and demonstration of conserved epitope may establish the domain as a credible target for cross species vaccination.