The goal of this project is to increase our understanding of the fibrinogen to fibrin clot conversion with the hope of providing a better foundation for clinical intervention in pathological clot formation. Recent advances in genetic engineering provide a unique opportunity to approach this problem in a way where the importance of each amino acid residue can be analyzed. That is, by manipulating the DNA which codes for fibrinogen, specific amino acid alterations can be made. I have isolated a human cDNA clone which codes for the entire A alpha polypeptide chain including a 19 amino acid signal peptide. This clone will be used to construct plasmids to direct the synthesis of the A alpha polypeptide in transfected cells. The expression of the A alpha chain will be detected immunologically. In periments I have constructed a vector which codes for a hybrid protein containing amino acids 1 to 551 of the A alpha polypeptide. Immunoreactivity has been detected in E. Coli transfected with this vector. The functional activity of the A alpha peptide separated from native fibrinogen will be tested by measuring its susceptability to thrombin cleavage and its ability to inhibit fibrin polymerization. Site specific mutants will then be constructed in the cDNA in order to produce altered A alpha peptides. Since thrombin recognition of the A alpha polypeptide has been extensively described, it will be straightforward to direct mutations towards residues which are known to be important to fibrinopeptide A cleavage. Similarly, areas of the A alpha chain which are considered to be important to fibrin polymerization can be tested by site directed mutagenesis. The effects of these alterations on the functional activity of the A alpha peptide will provide new information relevant to thrombin specificity and fibrin polymerization.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Unknown (R23)
Project #
5R23HL031048-02
Application #
3448554
Study Section
Hematology Subcommittee 2 (HEM)
Project Start
1984-04-01
Project End
1987-03-31
Budget Start
1985-04-01
Budget End
1986-03-31
Support Year
2
Fiscal Year
1985
Total Cost
Indirect Cost
Name
University of North Carolina Chapel Hill
Department
Type
Schools of Medicine
DUNS #
078861598
City
Chapel Hill
State
NC
Country
United States
Zip Code
27599
Huang, Lihong; Hsiao, Joe Ping-Lin; Powierza, Camilla et al. (2014) Does topology drive fiber polymerization? Biochemistry 53:7824-34
Smith, E L; Cardinali, B; Ping, L et al. (2013) Elimination of coagulation factor XIII from fibrinogen preparations. J Thromb Haemost 11:993-5
Hudson, Nathan E; Ding, Feng; Bucay, Igal et al. (2013) Submillisecond elastic recoil reveals molecular origins of fibrin fiber mechanics. Biophys J 104:2671-80
Raynal, Bertrand; Cardinali, Barbara; Grimbergen, Jos et al. (2013) Hydrodynamic characterization of recombinant human fibrinogen species. Thromb Res 132:e48-53
Huang, Lihong; Lord, Susan T (2013) The isolation of fibrinogen monomer dramatically influences fibrin polymerization. Thromb Res 131:e258-63
Park, Rojin; Ping, Lifang; Song, Jaewoo et al. (2013) An engineered fibrinogen variant A?Q328,366P does not polymerise normally, but retains the ability to form ? cross-links. Thromb Haemost 109:199-206
Lord, Susan T (2011) Molecular mechanisms affecting fibrin structure and stability. Arterioscler Thromb Vasc Biol 31:494-9
Ping, Lifang; Huang, Lihong; Cardinali, Barbara et al. (2011) Substitution of the human ?C region with the analogous chicken domain generates a fibrinogen with severely impaired lateral aggregation: fibrin monomers assemble into protofibrils but protofibrils do not assemble into fibers. Biochemistry 50:9066-75
Hantgan, Roy R; Stahle, Mary C; Lord, Susan T (2010) Dynamic regulation of fibrinogen: integrin ?IIb?3 binding. Biochemistry 49:9217-25
Hudson, Nathan E; Houser, John R; O'Brien 3rd, E Timothy et al. (2010) Stiffening of individual fibrin fibers equitably distributes strain and strengthens networks. Biophys J 98:1632-40

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