Figure 2. NMR and AFM characterization of human SLBP.

(A). (¹H,¹⁵N) HSQC spectra of the translation activation domain of hSLBP-ND collected at 600 MHz, pH 6.0, and 25°C is shown. In (B), the (¹H,¹⁵N) HSQC spectrum of hSLBP-ND W75A mutant collected under the same conditions as (A) is shown. The overlay of the WT (in blue) and W75A mutant (in red) spectra are shown in (C). In (D), the (¹H,¹⁵N) HSQC spectrum of human SLBP-ND WT collected at 700 MHz with cryoprobe is shown. Several additional peaks of low intensity appear at higher field. The {¹H-¹⁵N} heteronuclear NOE spectrum collected with NOE is shown in (E). Positive NOEs are in blue and negative NOEs are in green. In (F), (¹H,¹⁵N) HSQC spectrum of hSLBP-ND in the presence of equimolar amount of hSLIP1 was collected at a frequency of 600 MHz at 25 °C and pH 6.0. In (G), the AFM image of full-length baculovirus expressed hSLBP at 24 nM concentration is shown. Blue arrows point to the aggregates in the sample. The hSLBP monomers that are unstructured or partly structured are shown in the inset. Yellow arrows point to partially unstructured monomers. A histogram summarizing the volume measurements for the unbound structured component of hSLBP protein at 24 nM is shown in (H). For the 24 nM sample, N=118, bin size=10.