The mutant tRNA-Asn of P. carbinolicus and patterns of asparagine usage in proteins. The alignment (top) shows that Pcar_R0061 lacks features typical of the six tRNA-Leu species; it is a mutated copy of tRNA-Asn. The cloverleaf diagrams of tRNA-Asn (left) and the Pcar_R0061 transcript (right) illustrate that base-pairing is retained through reciprocal mutations and unlike the extended CCA-3′ end of tRNA-Asn, the 3′ end of a mature Pcar_R0061 transcript is predicted to be recessed and possibly longer by two bases. The Pcar_R0061 transcript may be modified similarly to tRNA-Asn, except for the queuosine and threonylcarbamyl modifications of the anticodon loop. The operon diagrams (middle) show that Pcar_R0061 is in one of two gene clusters encoding RNA 3′-phosphate cyclases. The graphs (bottom) show that the P. carbinolicus genome encodes fewer proteins with either more than 50 asparagine residues (left) or an asparagine demand index above 7.0 (right), compared to other Desulfuromonadales.