CD spectra of the recombinant CagA fragments.

<p>Ellipticity in the far-UV range (200–260 nm) is plotted for (a) CagA-N at 0.075 mg/ml, (b) CagA-M at 0.05 mg/ml, (c) CagA-M_c at 0.1 mg/ml and (d) Cag-R at 0.15 mg/ml.</p

Thermal unfolding and refolding transitions of CagA domains monitored by far-UV CD.

<p>The unfolding data is shown with black dots for CagA-N (a), CagA-M (b), CagA-M_c (c) and CagA-R (d). Unfolding was reversible for CagA-M, CagA-M_c and CagA-R; the refolding data is shown with open circles. The insets show the corresponding CD spectra for CagA-M (b), CagA-M_c (c) and CagA-R (d) for the native (solid line), unfolded (85 °C, dashed line) and refolded (dotted line) states. The low signal-to-noise ratio for the CagA-<i>R </i><i>spectrum</i> reflects the fact that the scan for this fragment was performed at lower wavelengths (205 nm rather than 222 nm), where the absorbance is inherently higher and thus the data is collected at a higher dynode voltage.</p

SDS-PAGE showing the time-course of digestion of CagA-M by trypsin.

<p>The arrow indicates a relatively stable core fragment CagA-M_c.</p

Crystal structure of the CagA region comprising the N-terminal (Domain I) and the middle (Domain II + Domain III) domains [19].

<p>Crystal structure of the CagA region comprising the N-terminal (Domain I) and the middle (Domain II + Domain III) domains [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0079367#B19" target="_blank">19</a>].</p

SEC and molecular weight (MW) and hydrodynamic radius determination of CagA-N (a), CagA-M_c (b) and CagA-R (c).

<p>Green dots superimposed on the peak indicate the MW as shown on the left-hand y-axis. Red dots represent the hydrodynamic radius calculated over the central portion of the elution peak (shown by UV trace in blue). The hydrodynamic radius values are shown on the right-hand y-axis.</p