In vitro complex formation. Combinations of recombinant proteins, 0.5 mg each, were allowed to assemble 1 h at 4°C. An aliquot each was analyzed by size exclusion chromatography and the elution of protein was monitored by absorption at 280 nm. A: ZmTSA + ZmTSB1, the retention volume of the major peak corresponds the size of an α2β2 tetramer. B: ZmTSAlike + ZmTSB1, two peaks corresponding an α monomer and a β2 dimer are observed. C: ZmTSB1 without addition of a TSA homolog; putative β2 dimers are formed.