Question

1) Proteins can interact with double-stranded DNA via non-covalent interactions. Among the different types of interactions listed below, which one(s) is/are most likely used by DNA-binding proteins to recognize DNA? Select all that apply.

Hydrogen bonds,Hydrophobic interactions,Electrostatic interactions,Disulfide bonds

2) What reagents are needed for a typical PCR reaction?Select all that apply

Two primers,Human DNA polymerase,Taq polymerase,DNA ligase,Four dNTPs,Buffer with Mg^2+,Template DNA,Four NTPs

3) A new investigator would like to express and purify a newly discovered protein. She decides to clone the gene into a plasmid that contains the sequence for a hexahistidine tag. Plasmids that contain a sequence for a hexahistidine tag will produce a recombinant protein with six extra histidine residues at the N- or C-terminus of the protein of interest.

Order the following steps for construction of the expression plasmid, expression and purification of the protein. The gene of interest will be introduced between the NotI and HindIII restriction sites.(1-5)

Purify the protein using a column of immobilized Ni²⁺.

Introduce NotI and HindIII rrestriction sites at the ends of the gene of interest via PCR.

Digest the plasmid and DNA encoding the genes with NotI and HindIII restriction endonucleases

Transform the plasmid into E. coli for protein expression.

Ligate the cut plasmid and DNA insert.