Zinc transporter (PubMed:29101379). Acts as a Zn(2+):proton symporter, which likely mediates zinc ion uptake (PubMed:29101379). Purified ZntB reconstituted in liposomes also binds and transports Cd(2+), Ni(2+) and Co(2+) (PubMed:29101379). H(+)(out) + Zn(2+)(out) = H(+)(in) + Zn(2+)(in) Homopentamer. Uses a transport mechanism that does not resemble the one proposed for homologous CorA channels. Belongs to the CorA metal ion transporter (MIT) (TC 1.A.35) family.