A 27.5-kb sequence that is present in an approx. 2-Mb chromosome in Le
ishmania also occurs as an inverted dimer in a multicopy, 55-kb circul
ar molecule (LD1) in Leishmania infantum ITMAP263. Sequence analysis o
f a 7100-bp cloned segment from the circular molecule revealed three o
pen reading frames (ORFs). The ORFs are likely to have protein coding
function by a number of criteria, including Northern blot analyses. Th
e amino acid (aa) sequences deduced from two ORFs showed no similarity
to other sequences in the databases. The C-terminal aa sequence from
the third ORF is related (22-29% identity, 57-71% similarity) to a fam
ily of genes conserved in bacteria and humans. One member (sfhB) of th
e gene family in Escherichia coli appears to have a role in regulation
of cell growth.