A protein that binds one of these compounds is engineered from a Tn10 gene product and the VP16 transactivator domain in a common inducible gene expression system. One type of these compounds forms the substrate of zinc-containing metalloenzymes that are class B in a classification scheme named for Ambler. A solution containing tryptone and yeast solution is commonly supplemented with these compounds to check for uptake of pUC19 or other vectors. One of these (-5[1])compounds prevents crosslinking of N-acetylglucosamine and N-acetylmuramic acid and contains a characteristic four-atom ring. That type of these compounds, beta-lactams, disrupt the peptidoglycan layer of the cell wall. For 10 points, penicillin is what kind of drug that kills bacteria? ■END■ (10[1])