Colicin M inhibits murein biosynthesis by interfering with bactoprenyl phosphate carrier regeneration. It belongs to the group B colicins the uptake of which through the outer membrane depends on the TonB, ExbB and ExbD proteins. These colicins contain a sequence, called the TonB box, which has been implicated in transport via TonB. Point mutations were introduced by PCR into the TonB box of the structural gene for colicin M, cma, resulting in derivatives that no longer killed cells. Mutations in the tonB gene suppressed, in an allele-specific manner, some of the cma mutations, suggesting that interaction of colicin M with TonB may be required for colicin M uptake. Among the hydroxylamine-generated colicin M-inactive cma mutants was one which carried cysteine in place of arginine at position 115. This colicin derivative still bound to the FhuA receptor and killed cells when translocated across the outer membrane by osmotic shock treatment. It apparently represents a new type of transport-deficient colicin M. Additional hydroxylamine-generated inactive derivatives of colicin M carried mutations centered on residues 193-197 and 223-252. Since these did not kill osmotically shocked cells the mutations must be located in a region which is important for colicin M activity. It is concluded that the TonB box at the N-terminal end of colicin M must be involved in colicin uptake via TonB across the outer membrane and that the C-terminal portion of the molecule is likely to contain the activity domain.

The haplotype ATA, which is known as a 'low interleukin-10 producer' is a putative risk indicator for generalized aggressive periodontitis.

Adhesion molecules like the members of the selectin family participate in the interaction between leukocytes and the endothelium. They are also involved in the pathogenesis of atherosclerotic processes. To contribute to the analysis of the genetic background of atherosclerosis we searched for DNA polymorphisms in the genes encoding adhesion molecules especially E-selectin which seems to be expressed only in activated endothelium. An adenine to cytosine substitution for cDNA position 561 resulting in an amino acid exchange from serine to arginine (position 128) was detected in the epidermal growth factor like domain. A significantly higher mutation frequency (P = 0.02) was observed in 97 patients aged 50 years or less with angiographically proven severe atherosclerosis (allele frequency of arginine 0.155) compared with an unselected population (allele frequency of arginine 0.088) as well as in 40 patients aged 40 years or less (allele frequency of arginine 0.21, P = 0.0025). These data suggest that the 128-serine/arginine polymorphism is associated with a higher risk for early severe atherosclerosis.

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Previous association studies between angiotensin-converting enzyme (ACE) and angiotensinogen (AGT) polymorphisms and several cardiovascular diseases have reported variable results. Therefore we examined the association of the DNA variants of ACE and AGT with early, severe coronary heart disease (CHD). In addition, we compared the genotypes of both polymorphisms and the recently discovered polymorphism in the E-selectin gene in both patients and an unselected population. This study included 113 patients with severe CHD (50 years old or less) and up to 197 control subjects. The frequencies of the ACE I/D variants were 48% I and 52% D in the controls and 46% I and 54% D in the patients. The frequencies of the AGT-M235T polymorphism were 60.8% M and 39.2% T in controls and 49.1% M and 50.9% T in the patients. The frequencies of the S128R polymorphism of the E-selectin were 91.3% S and 8.7% R in controls and 84.5% S and 15.5% R in the patients. In our studies the DD genotype of ACE was not associated with early severe CHD. We found a correlation between the M235T molecular variant of AGT and the S128R variant of E-selectin to early severe CHD.