Table 2.

Partial Clustal-W alignment of the proposed dinuclear binding motif in CmlA with other homologs in NRPS antibiotic biosynthetic pathways

CmlA and homologs
Species	Antibiotic	Consensus Sequence
Streptomyces venezuelae	chloramphenicol	H305-N-H-Q-D-H	x63	E	x25	D	x26	E
Actinoplanes teichomycetius	teicoplanin	H301-G-H-S-D-H	x65	E	x25	D	x26	E
Streptomyces verticillus	bleomycin	H316-A-H-H-D-H	x66	E	x25	D	x26	E
Nonomuraea sp. ATCC 39727	A40926	H301-G-H-S-D-H	x65	E	x25	D	x26	E
Streptomyces toyacaensis	A47934	H301-G-H-S-D-H	x65	E	x25	D	x26	E

Other dinuclear metal-binding enzymes with a lactamase fold
Enzyme or family (function)	Metal specificity	Consensus sequence
Metallo-lactamase (hydrolysis)	Zn∶Zn	H30–120-x-H-x-D/C/R/S-H	x57–70	H	x18–26	C/S	x37–41	H
Glyoxylase (hydrolysis)	Fe∶Zn	H54-x-H-x-D-H	x50	H	x22	D	x38	H
ROO (oxygen reductase)	Fe∶Fe	H79-x-E-x-D-H	x61	H	x22	D	x60	H
FprA (NO reductase)	Fe∶Fe	H81-x-E-x-D-H	x61	H	x18	D	x60	H

BLAST analysis was performed against GenBank bacterial sequences. Putative residues involved in metal ion binding are designated in red. For comparison, other dinuclear enzymes that utilize a lactamase folding motif with differing metal-binding specificities are also shown.