FIGURE 3.

A revised model for the “CO₂-transport metabolon.” As illustrated in the cartoon diagram, the CO₂-transport metabolon can be deemed as a transiently extended CAII machinery, which is built upon transient interactions among the four proteins: AQP1, erythroid AE1, CAII, and deoxy Hb^— (shown by red dotted lines). The C-terminal and N-terminal regions of AE1 are indicated by (C) and (N). Illustrated here in gray arrow lines is the direction of the conversion reaction in systemic capillaries: CO₂ is converted into HCO₃^—, followed by export of bicarbonate and absorption of proton by Hb^—.