Abstract
Esherichia coli strains with mutations that affect the occurrence of outer membrane proteins and the structure of the lipolysaccharide (LPS) in the outer membrane were tested to determine whether particular structures were essential for infection by coliphageT4. The infectivity was poor in the strains lacking OmpC. It was also poor in strains lacking the phosphate group on second heptose but containing P-PEEN on the first heptose on LPS, strains lacking the branching heptose on the second heptose on LPS, lacking the 3 glucose residues that are linked to the second heptose on LPS and strains containing all the sugar residues on LPS. Average infectivity was seen with strains lacking the terminal β -Glc on LPS and with strains lacking OmpF. Efficient infectivity was seen for strains lacking only OmpA, strains lacking all of the phosphate groups and PEEN on LPS as well as strains lacking a branching galactose and the terminal β -Glc on LPS. These results suggest that some components are essential but overall efficiency depends on several protein and lipopolysaccharide features.