Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.21.1 (chymotrypsin)
 10,938 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Initiation of Adenovirus DNA replication in vitro requires the presence of three viral proteins (pTP, pol, DBP) and two cellular transcription factors, NFI and Oct-1, that stimulate replication more than 100-fold. NFI assists in binding and positioning of the DNA polymerase in the origin whereas Oct-1 changes the structure of origin DNA. Optimal templates contain, in addition to origin sequences, the covalently bound viral terminal protein (TP). This terminal protein stimulates the template activity over 20 fold compared to protein-free templates. To study the way in which TP exerts its function in vitro we devised a novel method to isolate and label a short origin containing fragment in which the TP was bound in a functional form. This fragment replicated very efficiently and could be used for studying the binding of other replication proteins. Employing alpha-chymotrypsin digestion we show that for enhancement of replication in vitro only a small part of TP is required.
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PMID:Adenovirus DNA replication: the function of the covalently bound terminal protein. 129 Dec 41

Adenovirus DNA binding protein is a multifunctional protein essential for viral DNA replication. To investigate the role of the DNA binding protein in this process its interaction with partial DNA duplexes was examined. Duplex regions of DNA, created when a short DNA strand is annealed to its complementary sequence present in the single stranded form of M13 phage DNA, were efficiently unwound by DNA binding protein in a reaction that required neither ATP nor MgCl2. The unwinding activity of DNA binding protein was reduced by conditions which increased the stability of DNA duplexes. DNA unwinding by DNA binding protein was highly co-operative and required the single stranded DNA to be completely coated with the protein. Completely double stranded DNA could also be unwound by DNA binding protein but this reaction was sensitive to the G+C content of the DNA and could only be observed with relatively short DNA duplexes up to 45 base pairs in length. When these short double stranded DNA molecules contained binding sites for the transcription factors NFI and NFIII addition of the cognate factor blocked DNA binding protein mediated unwinding of the particular DNA duplex. Cleavage of DNA binding protein with chymotrypsin and isolation of the 39,000 molecular weight C-terminal fragment indicated that the unwinding activity was located in this domain of the protein. In support of this contention a monoclonal antibody, which had previously been mapped to this region, specifically inhibited the DNA unwinding activity. These activities of DNA binding protein are likely to be involved in DNA replication, where the destabilisation of DNA duplexes could be important both during initiation and elongation.
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PMID:Adenovirus DNA binding protein: helix destabilising properties. 813 13