Exjobbsförslag från företag

Detta är ett uppsatsförslag hämtat från Nationella Exjobb-poolen. Klicka här för att komma tillbaka till samtliga exjobbsförslag.

Förslaget inkom 2003-01-07

EVOLUTION OF AN ENDONUCLEASE

OBS! ANSÖKNINGSTIDEN FÖR DETTA EXJOBB HAR LÖPT UT.
Endonuclease II (EndoII) encoded by coliphage T4 causes sequence-specific cleavage of foreign DNA only, like a bacterial restriction endonuclease, but shares amino acid motifs with homing endonucleases and resembles these also in the way it recognizes its targets. However, in comparison to related homing endonucleases, EndoII is much smaller, containing sequences corresponding only to the amino-terminal catalytic domain while lacking the carboxy-terminal DNA-binding domain. We have sequenced the homologous gene in a large number of T4-related phage: most encode an identical enzyme. One
distantly related phage appears to encode a longer protein with overall only 50% identity to EndoII (retaining, however, all amino acids universally conserved in this group of endonucleases and thus expected to show endonucleolytic activity); this phage contains unmodified DNA that should be a substrate for an enzyme with the properties of T4 EndoII.

The project involves characterization of this enzyme, and other homologous enzymes from similarly distantly related phage (our preliminary screen has picked up an additional 6 such phage to test). Does it encode an endonuclease with a homing function, rather than restricting? If time permits, a homing version of T4 EndoII will be constructed, fusing the EndoII reading frame to the carboxy-terminal DNA binding domain of a related homing endonuclease. Methods to be employed include in vitro transcription-translation, enzyme assays, cloning, sequencing, DNA-labelling, and electrophoresis.


  GÅ TILL XJOBB.NU FÖR FULLSTÄNDIG INFO OM DETTA EXJOBB




Informationen om uppsatsförslag är hämtad från Nationella Exjobb-poolen.