Fig. 3.

Crosslinked samples of Hsp21 and MDH analyzed by SDS-PAGE. Samples were pre-incubated at 20 °C or 45 °C M, as indicated, crosslinked, and then loaded to SDS-PAGE. MW, molecular weight marker; lane 1, Hsp21 + MDH, non-crosslinked reference sample; lane 2, Hsp21 + MDH, sample crosslinked after pre-incubation 30 min at 20 °C; lanes 3, 4, and 5 Hsp21 + MDH, triplicate samples crosslinked after pre-incubation 30 min at 45 °C; lane 6, Hsp21+MDH, sample crosslinked after pre-incubation 180 min at 45 °C. Extra bands are visible at 10 and 18 kDa which are degradation products of Hsp21 and at 42 kDa a dimer of Hsp21. The non-covalent bonds within the Hsp21 dimer are strong enough for a band to be visible in SDS-PAGE, more or less depending on the exact number of minutes and degrees in solubilization buffer. The Hsp21 dimer becomes stabilized by crosslinking and visible as an even stronger band (lanes 2–6)