Fig. 4

AP7 alignment and spectra, a Alignment of H. laevigata Tri_24151 to H. rufescens AP7 (Q9BP37_HALRU; [17]). Predicted signal sequence peptides are in red. Sequence regions confirmed by MS/MS-derived peptide sequences are in green. Cysteines proposed to be part of the metal binding site [98] are underlined. The N-terminal mineral-interacting domain [97] is shown in italics. b MS/MS spectrum of a selected sequence-unique peptide most probably representing the N-terminus of this protein and confirming the secretion signal peptide prediction. This doubly charged peptide was identified with a mass error of 0.5 ppm and a Posterior Error Probability (PEP) of 1.7e-42. Y-ions are shown in red, b-ions are in blue, and fragments with neutral loss are in orange. Ion a3 was identified using the advanced annotation option of the MaxQuant viewer (Expert system [44]). c MS/MS spectrum of a selected sequence-unique peptide from the insert sequence region not present in H. rufescens AP7. The doubly charged peptide was identified with a mass error of 0.01 ppm and a PEP of 2.7e-36. The mass spectrometer model used, Velos or Elite, is contained in the raw-file name on top of the y-axis of the spectra