Figure 2.

Characterization of the mIHF gene of M. smegmatis. (a) M. smegmatis mIHF is a single-copy gene. DNA isolated from M. smegmatis mc²155 was digested with the restriction enzymes indicated and hybridized with a radiolabeled mIHF probe. Only one hybridizing band is observed in each lane, indicating that there is only a single mIHF gene. (b) Sequence of the mIHF gene of M. smegmatis and the predicted amino acid sequence of mIHF. The DNA sequence of a 1054-bp segment of the M. smegmatis genome (GenBank accession number U75344U75344) and the putative amino acid sequence of the 105-residue mIHF protein are shown. The underlined amino acids (residues 2–39) correspond to those determined by N-terminal amino acid sequencing of the mIHF protein. No other genes were identified in this DNA segment. (c) Sequence alignment of the mIHF genes of M. smegmatis and M. tuberculosis. The DNA sequence shown in b was compared with a segment of M. tuberculosis DNA, using a window of 21 nt and a stringency of 14 nt. Arrows indicate the 5′ and 3′ ends of the mIHF coding regions. The M. tuberculosis sequence used was from coordinates 3600 to 4600 of cosmid MTCY21B4 (GenBank accession number Z80108Z80108). (d) Sequence alignment of mIHF proteins of M. smegmatis and M tuberculosis. The M. smegmatis sequence is that shown in b and the M. tuberculosis sequence was derived by translation of coordinates 4207–4524 of cosmid MTCY21B4 (GenBank accession number Z80108Z80108). Amino acid identities are indicated by a vertical line.