The putative phosphorylation site, H286, is required for in vivo activity of SdeK. M. xanthus strains DK1622 (wild type [WT]), MS1512 (ΔsdeK1), MS1527(ΔsdeK1 sdeK+), and MS1526 (ΔsdeK1 sdeKH286A) were developed for 3 days on TPM agar. Photographs were taken 72 h after development initiation. Magnification, ×96.