2-Gaussian fit: Grosse-Kunstleve RW, Sauter NK, Adams PD: Newsletter of the IUCr Commission on Crystallographic Computing 2004, 3, 22-31.

The smallest functional antibody fragment: Ultralong CDR H3 antibody knob regions potently neutralize SARS-CoV-2.

QAVLNQPSSVSGSLGQRVSITCSGSSSNVGNGYVSWYQLIPGSAPRTLIYGDTSRASGVPDRFSGSRSGNTATLTISSLQ
AEDEADYFCASAEDSSSNAVFGSGTTLTVLGQPKAAPSVTLFPPSSEELQANKATLVCLISDFYPGAVTVAWKADSSPVK
AGVETTTPSKQSNNKYAASSYLSLTPEQWKSHRSYSCQVTHEGSTVEKTVAPTECS

(PCA)VQLRESGPSLVKPSQTLSLTCTVSGFSLSDKAVGWVRRAPGKALEWLGSIDTGGMTGYNPGLKSRLSITKDNSKS
QVSLSVNSVTTEDSATYYCATVDQKTKNACPDDFDYRCSCIGGCGCARKGCVGPLCCRSDLGGYLTDSPAYIYEWYIDLW
GQGLLVTVSSASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTVSWNSGALTSGVHTFPAVLQSSGLYSLSSVVT
VPSSSLGTQTYICNVNHKPSNTKVDKKVEPKSC

QVQLRESGPSLVKPSQTLSLTCTVSGFSLSDKAVGWVRRAPGKALEWLGSIDTGGMTGYNPGLKSRLSITKDNSKSQVSL
SVNSVTTEDSATYYCATVDQKTKNACPDDFDYRCSCIGGCGCARKGCVGPLCCRSDLGGYLTDSPAYIYEWYIDLWGQGL
LVTVSSASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTVSWNSGALTSGVHTFPAVLQSSGLYSLSSVVTVPSS
SLGTQTYICNVNHKPSNTKVDKKVEPKSC

0.2M sodium chloride, 0.1M phosphate-citrate buffer, 20% Peg6000

SEELQANKATLVCLISDFYPGAVTVAWKADSSPVKAGVETTTPSKQSNNKYAASSYLSLTPEQWKSHRSYSCQVTHEGST
VEKTVAPTECS

LVTVSSASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTVSWNSGALTSGVHTFPAVLQSSGLYSLSSVVTVPSS
SLGTQTYICNVNHKPSNTKVDKKVEPKSC