This is the membrane-anchor domain of translocase of chloroplast 159, TOC159/132. This domain is present in plants at the C-terminus of the GTPase, AIG1, Pfam:PF04548, and anchors the GTPas region to the outer membrane of the chloroplast. The domain may carry a very C-terminal sequence motif that resembles a transit peptide [1].

1: Targeting and assembly of components of the TOC protein import complex at the chloroplast outer envelope membrane. Richardson LG, Paila YD, Siman SR, Chen Y, Smith MD, Schnell DJ; Front Plant Sci. 2014;5:269. PMID:24966864