Location and identification of muropeptides in FACE gels. Lane 1, carbohydrate reference ladder (Glyko, Inc.). Lane 2, E. coli CS109 muropeptides labeled with ANTS and separated by FACE. Arrows indicate the identities of bands as determined by correspondence with muropeptide results when fractionated by reversed-phase HPLC (HPLC), by the behavior of bands in E. coli mutants (Mutants), or by mass spectrometry (Mass Spec). The double asterisk (**) denotes an unidentified band.