GCA_000018585.1 P9211_00021 definition phosphoribosylformylglycinamidine synthetase II GCA_000018585.1 P9211_09811 definition phosphoribosylformylglycinamidine synthase GCA_000018585.1 P9211_09821 definition Phosphoribosylformylglycinamidine synthetase PurS GCA_000018585.1 P9211_17101 definition phosphoribosyl formylglycinamidine cyclo-ligase