Table 1.

Summary of all simulations in this paper

Set	Mutant	System	Length ($\mathrm{\mu }$s)	Temperature, K	MD simulation type
1	WT*	S2† + S3‡	23.0	300–600	CST
1	WT	S2 + S3	8.0	300–550	CST + Umbrella $N_{\mathrm{h}\mathrm{b}}=60$
1	WT	S2 + S3	7.0	300–550	CST + Umbrella $N_{\mathrm{h}\mathrm{b}}=55$
2	WT	S2 + S3	1.0	350	Unbiased
2	WT	S2 + S3	3.0	350	Unbiased
2	WT	S2 + S3	7.2	350	Unbiased
3	WT	S1§ + S2 + S3	6.0	350	Unbiased
3	WT	S1 + S2 + S3	7.5	350	Unbiased
4	WT	S2 + S3	0.5	300 $\to$ 600	Thermal unfolding
4	WT	S1 + S2 + S3	0.5	300 $\to$ 600	Thermal unfolding
4	Thr59Met	S2 + S3	0.5	300 $\to$ 600	Thermal unfolding
4	Thr59Val	S2 + S3	0.5	300 $\to$ 600	Thermal unfolding

^*Group 2 H3 HA, sequence from ref. 2.

^†B loop (residues 54–75 of HA₂).

^‡Unchanged region between prefusion and postfusion HA structures (residues 76–105 of HA₂).

^§A helix (residue 38–53 of HA₂).