Topological analysis of the human γ-glutamyl carboxylase.

(A) TOPPRED II analysis of human GC. The hydropathy plot generated by TOPPRED II with a default window of 21 is shown. We predicted 7 TMDs at amino acid residues 60-80 (TM1), 115-135 (TM2), 138-158 (TM3), 197-217 (TM4), 252-272 (TM5), 293-313 (TM6), and 361-381 (TM7). (B) Schematic representation of the GC and hGC-Lep constructs used to experimentally determine the topology. The solid bars indicate the TM segments predicted by TOPPRED II, and Y indicates potential N-linked glycosylation sites. The P2 domain of Lep was fused to the C-terminus of the hGC fragments in all constructs.