This family was first named TPM domain after its founding proteins: TLP18.3, Psb32 and MOLO-1. In Arabidopsis, this domain is called the thylakoid acid phosphatase -TAP - domain and has a Rossmann-like fold [1]. In plants, the family resides in the thylakoid lumen attached to the outer membrane of the chloroplast/plastid. It is active in the photosystem II [2,3].

1: Structural and Functional Assays of AtTLP18.3 Identify Its Novel Acid Phosphatase Activity in Thylakoid Lumen. Wu HY, Liu MS, Lin TP, Cheng YS; Plant physiol. 2011;9:0-0. PMID:21908686

2: TLP18.3, a novel thylakoid lumen protein regulating photosystem II repair cycle. Sirpio S, Allahverdiyeva Y, Suorsa M, Paakkarinen V, Vainonen J, Battchikova N, Aro EM; Biochem J. 2007;406:415-425. PMID:17576201

3: The Psb32 protein aids in repairing photodamaged photosystem II in the cyanobacterium Synechocystis 6803. Wegener KM, Bennewitz S, Oelmuller R, Pakrasi HB; Mol Plant. 2011;4:1052-1061. PMID:21653280