(Kenyon and Hall, unpublished). OCL1 contains 5 genes
predicted to encode glycosyltransferases that would form
linkages in the OC1 structure. OC1 includes glucosamine (DGlcpN)
and galactosamine (D-GalpN) sugars, and the pda1
gene (Fig. 1) encodes an enzyme predicted to deacetylate
UDP-N-acetyl-glucosamine (UDP-D-GlcpNAc) and/or UDPN-
acetyl-galactosamine (UDP-D-GalpNAc), producing the
UDP-linked form of these products. OCL1 also contains 3
genes without known relatives. One facing in the opposite
direction to the remaining genes in OCL1 may encode a
glycosyl hydrolase, and the remaining 2 have tentatively been
assigned as glycosyltransferases [2].
Here, we have determined the genome sequences of A.
baumannii isolates belonging to the clinically important global
clones, global clone 1 (GC1) and global clone 2 (GC2) from
our Australian collection. GC1 and GC2 correspond to CC1
and CC2 in Ref. [8]. Naturally occurring OCL mutants identified
among them were used to examine the size of the LOS
they produce. This provided experimental evidence confirming
the assignment of the OC locus as the region that directs the
synthesis of the OC of the LOS.