Plays a role in the autotrophic CO(2) fixation pathway. Activates 3-hydroxypropionate to its CoA ester. Can also activate propionate, and to a lesser extent acrylate, acetate and butyrate. 3-hydroxypropanoate + ATP + CoA = 3-hydroxypropanoyl-CoA + AMP + diphosphate Belongs to the ATP-dependent AMP-binding enzyme family.