FIG. 4.

Multiple sequence alignment of amino acid sequences of the cPGI family. The alignment was generated by using CLUSTAL X (50). Accession numbers were as follows: PfcPGI, NP577925; AfcPGI, NP070323; MmcPGI, NP633992; StcPGI, NP461684; EmcPGIA, Q92MQ8; EmcPGIB, Q92UI1 (and its putative homologs from P. horikoshi [O59618], P. abyssi [Q9UXW3], M. barkeri [ZP00076760], and M. acetivorans [NP615780]). The two derived signature patterns of the cPGI family are given below the alignment; invariable residues of these patterns are in boldface and are also highlighted in the alignment. Secondary structure assignments as derived from the X-ray structure of the PfcPGIs (49) are given above the sequences; α-helices are indicated as bars, and β-sheets are indicated as arrows.