Ava_3939 Protein hesB, heterocyst MTVTLTEKAEFRLRAFLRGSAKDANETTKGIRISVKDGGCSGYEYLMDVTSQPQPDDLVSQQGSVLVYVDAKSAPLLEGIVIDFVEGLVESGFKFTNPNATSTCGCGKSFKAGDCSPEGVPCS HESB1_ANAVT 123 hesB1 May be required for efficient nitrogen fixation.