Mo. Rev. Stat. § 486.130

Every commissioner shall have power to administer any oath which may be lawfully required in this state, to any person willing to take it; and to take and certify all depositions to be used in any of the courts of this state, in conformity to the laws thereof, either on interrogatories proposed under commission from a court of this state, or by consent of parties, or on legal notice given to the opposite party; and all such acts may be as valid as if done and certified according to law by an associate circuit judge in this state.