Fig. 6

a Expression profile (normalized TPM values) of AA9 genes from Coniochaeta sp. 2T2.1 after growth (0.1 OD, 600 nm) on wheat straw (WS), and dilute-acid-pretreated wheat straw solids (PTWS). Asterisks represent putative secreted enzymes that were significantly upregulated (padj-value ≤ 0.05 and Log2 FC ≥ 8) in WS and PTWS compared with glucose (Glu) cultures; s, d and t letters represent single, duplicate and triplicate genes within the 2T2.1 genome. b Structural 3D modeling of five selected AA9 proteins that were significantly and highly upregulated (padj-value ≤ 0.05 and Log2 FC ≥ 8) on wheat straw (WS) compared with glucose (Glu) cultures. Phyre2 [41] and EZmol [42] web portals were used to predict the putative 3D structural conformation. The molecular size of these proteins (JGI-IDs 1170506, 980755, 1220247, 1175568, and 1230134) ranged between 22 and 29 kDa with different isoelectric points (from 4.56 to 7.51). We identified predicted metal-binding and histidine brace sites based on the structural position and comparison with the best protein for modeling (Additional file 7: Table S6). In the five AA9 proteins, these sites were identified and contain generally two to three histidines (green), one to two tyrosines (red) and one residue of glutamine (blue)