Table 1. Arabidopsis thaliana homologs of SWR1-C subunits co-purify with N-TAP ARP6 and C-TAP ARP6.

IP-ed proteins	Gene ID	Predicted MW (kDA)	Peptide number (N-TAP 11–4)	Peptide number (N-TAP 1–2)	Peptide number (C-TAP 10–2)
ARP6 PIE1 SWC2 SWC4 SWC6 RuvB1 RuvB2 HTA8 HTA9 HTA11 HTB2 HTB4 HTB9 ARP4 ACT1 YAF9a YAF9b MBD9 TRA1A TRA1B AL5 AL6 AL7	AT3G33520 AT3G12810 AT2G36740 AT2G47210 AT5G37055 AT5G22330 AT5G67630 AT2G38810 AT1G52740 AT3G54560 AT5G22880 AT5G59910 AT3G45980 AT1G18450 AT2G37620 AT5G45600 AT2G18000 AT3G01460 AT2G17930 AT4G36080 AT5G20510 AT2G02470 AT1G14510	46.9 234 42.1 49.8 19.1 50.3 52.1 14.4 14.3 14.5 15.7 16.4 16.4 48.9 41.8 30.2 30.4 240.4 436.3 433.6 29.6 28.8 28.3	34 28 5 7 2 25 23 ND 2 ND 6 8 8 14 9 1 ND 12 18 17 3 4 3	35 12 3 5 3 22 22 ND ND 1 ND 5 ND 11 9 ND ND 4 1 1 2 2 ND	28 31 3 5 3 21 23 ND ND 3 5 5 5 13 8 6 ND 6 15 11 2 2 3

We used mass spectrometry (MS) analysis to identify eluted proteins co-purified with ARP6-TAP-tag. All proteins identified by MS from three independent experiments (S1 Table) were first filtered against the proteins purified from WT by TAP and then against the list of 760 known non-specific binders of the GS-TAP-tag. Table 1 contains the proteins that are not found on the list of the TAP-tag background proteins and are known homologs of SWR1 complex subunits in yeast and SRCAP subunits in mammals. The table also includes proteins such as MBD9, TRA1A and TRA1B, and Alfin1-like family proteins (bottom six rows) that may represent novel subunits of the SWR1 complex. The table shows the expected MWs for each identified protein, and the total number of peptides identified by MS from two N-TAP-ARP6 and one C-TAP-ARP6 transgenic plants. ND = not detected.