Probably forms vertices in the shell of the bacterial microcompartment (BMC) dedicated to 1,2-propanediol (1,2-PD) degradation. Expression of a cosmid containing the full 21-gene pdu operon in E.coli allows E.coli to grow on 1,2-propanediol (1,2-PD) with the appearance of BMC in its cytoplasm. Overexpression of this protein has no effect on the appearance of BMCs. The 1,2-PD-specific bacterial microcompartment (BMC) concentrates low levels of 1,2-PD catabolic enzymes, concentrates volatile reaction intermediates thus enhancing pathway flux and keeps the level of toxic, mutagenic propionaldehyde low. Polyol metabolism; 1,2-propanediol degradation. Homopentamer (By similarity). Interacts with shell protein PduA (PubMed:20417607). The N-terminus is required for integration into BMCs; a C-terminal GFP fusion protein is targeted to BMCs whereas an N-terminal GFP fusion does not permit BMC formation. Artificial BMCs can be made in E.coli by expressing pduA-pduB/B'-pduJ-pduK-pduN-pduU-pduT (in this order); pduT and pduU are optional, while pduA, pduB/B', pduJ, pduK and pduN are essential. A construct with the reversed gene order does not make BMCs (PubMed:20417607). Ethanogenic BMCs can be made in E.coli by targeting pyruvate decarboxylase (pdc) and alcohol dehydrogenase (adh) to them. PduP(1-18)-Pdc and PduD(1-18)-Adh strains targeted to the BMC (PduA, PduB, PduJ, PduK, PduN, PduU) make significantly more ethanol than strains where Pdc and Adh are not targeted to the BMC (PubMed:24933391). Belongs to the CcmL/EutN family.