The stoichiometry of the minimal complex has been experimentally difficult to determine .
The stoichiometry of the minimal complex has been determined by biochemical analysis , single - molecule experiments , and X-ray crystallography to be a heterotrimer of two DGCR8 proteins to one Drosha .
The stoichiometry of the minimal complex has been experimentally difficult to determine , but has been determined by biochemical analysis , single - molecule experiments , and X-ray crystallography to be a heterotrimer of two DGCR8 proteins to one Drosha .