Comparison of N-termini, C-termini and repeat units of spider silk proteins.

<p>(A) Alignment of published N-terminal amino acid sequences. Amino acids shared by ≥50% of proteins are highlighted in grey. Gaps are represented by dashes and missing characters by question marks. (B) Alignment of corresponding C-terminal amino acid sequences. Taxa with an asterisk result from partial sequencing and are presumed to belong to the same locus as the N-terminal sequences. (C) MP trees of N and C-terminal encoding sequences treating gaps as a fifth state and employing midpoint rooting. Left tree length = 1449 (N-terminus); Right tree length = 838 (C-terminus). Dots represent nodes with >75% bootstrap support in all MP and ML analyses and >95% Bayesian posterior probability. (D) Exemplar repeat units for each of the major ampullate fibroins and representative TuSp1 and Flag repeats. Amino acid motifs are colored as in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0000514#pone-0000514-g002" target="_blank">Figure 2</a>. Abbreviations: LhMaSp2, <i>Latrodectus hesperus MaSp2</i> (EF595245); LhMaSp1, <i>L. hesperus MaSp1</i> (EF595246); LgMaSp1, <i>L. geometricus MaSp1</i> (5′ sequence: DQ059133S1, 3′ sequence: DQ059133S2); NiMaSp2, <i>Nephila inaurata madagascariensis MaSp2</i> (5′ sequence: DQ059135, 3′ sequence: AF350278); AtMaSp2, <i>Argiope trifasciata MaSp2</i> (5′ sequence: DQ059136, 3′ sequence: AF350266); EaMaSp1; <i>Euprosthenops australis MaSp1</i> (AM259067); LhTuSp1, <i>L. hesperus TuSp1</i> (5′ sequence: DQ379383, 3′ sequence: AY953070); AbCySp1, <i>A. bruennichi CySp1</i> AB242144; AbCySp2, <i>A. bruennichi CySp2</i> (AB242145); NcaCySp1, <i>N. clavata CySp1</i> (5′ sequence: AB218974, 3′ sequence: AB218973); NiFlag, <i>N. i. madagascariensis Flag</i> (5′ sequence: AF218623S1, 3′ sequence: AF218623S2); NclFlag, <i>N. clavipes Flag</i> (5′ sequence: AF027972, 3′ sequence: AF027973).