The invention provides for polynucleotides and vectors comprising at least two tag sequences. The invention also provides for polynucleotides and vectors comprising a streptavidin binding peptide sequence and a calmodulin binding peptide sequence. The invention also provides for polynucleotides and vectors wherein a gene of interest is fused in frame to at least two tag sequences, for example, a streptavidin binding peptide sequence and a calmodulin binding peptide sequence. The invention also provides for the chimeric proteins encoded by these polynucleotides. The invention also provides for methods of using the polynucleotides of the invention for detecting and/isolating protein complexes or identifying a binding partner for a protein of interest.