Phylogenetic tree obtained for MBL subgroup B1. The numbers for the substitutions should be multiplied by 100. The alignment used was prepared with the CLUSTALW program. The GenBank accession numbers for the sequences are as follows: IMP-1, S71932; IMP-2, AJ243491; IMP-8, AF322577; VIM-1, Y18050; VIM-2, AF191564; GIM-1, AJ620678; SPM-1, AJ492820; SIM-1, AY887066; KHM-1, AB364006