Fig. 4. Alignment of the C-terminal amino acid sequences encoded by various phaE genes. The sequences of Synechococcus sp. MA19 and Chlorogloeopsis fritschii PCC 6912, which were determined in this study, were aligned with those of Synechocystis sp. PCC 6803, Allochromatium vinosum, Thiocystis violacea, Thiococcus pfennigii and Ectothiorhodospira shaposhnikovii. The PhaE box shows a region of absolutely identical amino acids occurring among PhaE subunits. The stretches Gln-Val-Ala-Ala-Leu-Ala-Gly and Ala-Pro-Ala-Pro-Ala-Thr occurring in the PhaE proteins of anoxygenic sulfur bacteria, which might be related to PHA granule binding sites (Liebergesell et al., 2000 R18 ), are boxed for comparison with the corresponding regions in the PhaE proteins of cyanobacteria. Absolute conservation, high conservation and low conservation are indicated by ‘*’, ‘:’ and ‘.’, respectively. n i and n j are the numbers of amino acids in C-terminal regions of PhaEMA19 and PhaECf, respectively.