Cell wall inhibition in a stable streptococcal L-form.

Abstract

Both protoplast and stable l-form cells were derived from a group A streptococcus. It was found that lack of cell wall biosynthesis could be correlated with the inability of the l-form to transfer rhamnosyl units from preformed TDP-rhamnose to membrane acceptor sites enzymatically. Protoplast membrandes, on the other hand, readily incorporated rhamnose units into protoplast-membrane polysaccharide. Both l-form and protoplast cell free extracts were capable of synthesizing TDP-rhamnose at approximately equal rates. Intact l-form cells contained only 117th as much polymeric rhamnose as found within whole protoplasts. These findings agree with and substantiate current thoughts implicating a rhamnose-containing nucleotide in coccal cell-wall biosynthesis and suggest that l-form cell wall inhibition may due to lack of sufficient membrane acceptor sites, or the membrane enzyme(s) necessary to effect such a transfer, or both.