Catalyzes the phosphorylation of D-fructose 6-phosphate to fructose 1,6-bisphosphate by ATP, the first committing step of glycolysis. ATP + beta-D-fructose 6-phosphate = ADP + beta-D-fructose 1,6-bisphosphate + H(+) In contrast with PFK1 this enzyme is not affected by phosphoenolpyruvate. Carbohydrate degradation; glycolysis; D-glyceraldehyde 3-phosphate and glycerone phosphate from D-glucose: step 3/4. Homotetramer. Belongs to the phosphofructokinase type A (PFKA) family. ATP-dependent PFK group I subfamily. Prokaryotic clade 'B1' sub-subfamily.