Hearst Corp. acquired Houston Chronicle Publishing Co., which owns the Houston Chronicle, from Houston Endowment Inc. for $415 million, increasing by $15 million the $400-million price announced March 12. Texas Atty. Gen. Jim Mattox, who has review power over transactions involving charitable trusts such as the endowment, has stated that he is satisfied with the terms of the revised agreement. Of the total price, $300 million was paid in cash at closing. $115 million will be carried in a promissory note maturing at 15 years, with an interest rate of 7%.