BRASILIA - Deputy finance ministers from the Group of 20 leading economic powers will hold a conference call on Saturday to discuss the crises in Europe and the United States, a Brazilian finance ministry official said.The official told Reuters the call was scheduled for 2230 GMT."It will be an exchange of information and opinions," the official said by e-mail without providing further details.Investors are eager to see signs of a coordinated policy response among major economies, which might prevent the crises from spreading or getting worse.