Sulfate adenylyltransferase. Catalyzes the first step of the sulfate assimilation pathway. ATP + H(+) + sulfate = adenosine 5'-phosphosulfate + diphosphate Sulfur metabolism; hydrogen sulfide biosynthesis; sulfite from sulfate: step 1/3. Homotetramer. Expressed in roots and leaves. Belongs to the sulfate adenylyltransferase family.