N table S1. Melting curves of Zarvin and the single domains were performed by diluting the proteins in 20 mM HEPES, 20 mM NaCl, pH 7.4 at a final concentration of 0.09 mg/ml and using a 2 mm cuvette. Recording parameters used were data pitch: 0.1uC, delay time: 180 s, bandwidth: 1 nm, response time: 8 s, temperature slopes: 0.5uC/min for melting and 1uC/min for cooling.of 105?06 cells/cm2 on m-Slide 8 well plates (Ibidi). Afterwards, medium was removed and cells were incubated with a mixture of Cetuximab and Zarvin-D72C-Atto594, Cetuximab alone, ZarvinD72C-Atto594 alone or buffer without any protein for 30 minutes at room temperature. The used buffer was 25 mM HEPES, 150 mM NaCl, 4 mM KCl, pH 7.4. A431 cells are viable in this buffer for days. Protein concentrations were 7.8 mM Cetuximab and 14 mM Zarvin-D72C-Atto594 in HEPES buffer. Finally, unbound protein was removed by 5 washing steps with HEPES buffer and cells were left in this buffer containing 10 FCS during microscopy. Atto-594 was excited with a 594 nm laser and an intensity of 50 . Emission was detected between 605?50 nm with a PMT voltage between 800 volts. Auto fluorescence of cells was measured by exciting with a 405 nm diode laser and detecting fluorescence between 417?02 nm. The laser intensity used was 70 and the PMT voltage 820 V. Pictures were recorded with a Val of SMARTA following Lm-gp61 or LCMV infection is determined within resolution of 8 bit, a size of 102461024 pixel, a line average of 8 and a scanning speed of 200 pixel/sec. Z-stacks were recorded with a stack thickness of 0.17 mM, a size of 102461024 pixel, a line average of 2 and a scanning speed of 400 pixel/sec. Image processing concerning brightness and contrast adjustments were done using the program Image J.Luminescence Measurements and Metal TitrationsLuminescence measurements were performed using a Cary eclipse fluorescence spectrometer. Terbium (III) in complex with Zarvin was excited via energy transfer from a phenylalanine between the EF and CD metal Title Loaded From File binding sites of the Parvalbumin domain. The excitation wavelength used for this was 258 nm. Luminescence emission was detected at 543 nm (5D4 R 7F5 transition) with a delay time of 0.2 ms, a gate time of 4.5 ms and a total decay time of 200 ms. The excitation and emission slit widths used were 10 nm and 20 nm respectively. The PMT voltage was 800 V. Titrations were carried out at 20uC. Each titration step was measured in kinetic mode with an average time of 7 s over a time scale of 10 minutes. Affinity determinations of Tb3+ to the EF and CD site of the Parvalbumin domain were done in 20 mM Tris, 150 mM NaCl, pH 7.4. Each titration step was pipetted separately and all batches were incubated for three days at room temperature to establish equilibrium between the complexes Zarvin:(Tb3+)2 and NTA:Tb3+. The curve was normalised and inverted prior to fitting with a Hill equation. Using the fitted apparent affinity of NTA:Tb3+ and the real binding affinity [15] of this complex of 5.6 6 10212 M, the binding affinity of Zarvin:(Tb3+)2 was estimated according to equation: KDZarvin KDNTA : arvin Kapp {KDNTA ??Labelling of ZarvinN-terminal labelling of Zarvin as well as labelling of the cysteine residue 23977191 of Zarvin-D72C was performed using NHS-Ester and maleimide derivatives of Atto dyes respectively (Atto-tec, Siegen, Germany). Labelling was performed according to the Atto-tec protocols for amine and thiol reactive dyes respectively. The chosen labelling strategy was 1 h at room temperature and subsequent separation of the prote.N table S1. Melting curves of Zarvin and the single domains were performed by diluting the proteins in 20 mM HEPES, 20 mM NaCl, pH 7.4 at a final concentration of 0.09 mg/ml and using a 2 mm cuvette. Recording parameters used were data pitch: 0.1uC, delay time: 180 s, bandwidth: 1 nm, response time: 8 s, temperature slopes: 0.5uC/min for melting and 1uC/min for cooling.of 105?06 cells/cm2 on m-Slide 8 well plates (Ibidi). Afterwards, medium was removed and cells were incubated with a mixture of Cetuximab and Zarvin-D72C-Atto594, Cetuximab alone, ZarvinD72C-Atto594 alone or buffer without any protein for 30 minutes at room temperature. The used buffer was 25 mM HEPES, 150 mM NaCl, 4 mM KCl, pH 7.4. A431 cells are viable in this buffer for days. Protein concentrations were 7.8 mM Cetuximab and 14 mM Zarvin-D72C-Atto594 in HEPES buffer. Finally, unbound protein was removed by 5 washing steps with HEPES buffer and cells were left in this buffer containing 10 FCS during microscopy. Atto-594 was excited with a 594 nm laser and an intensity of 50 . Emission was detected between 605?50 nm with a PMT voltage between 800 volts. Auto fluorescence of cells was measured by exciting with a 405 nm diode laser and detecting fluorescence between 417?02 nm. The laser intensity used was 70 and the PMT voltage 820 V. Pictures were recorded with a resolution of 8 bit, a size of 102461024 pixel, a line average of 8 and a scanning speed of 200 pixel/sec. Z-stacks were recorded with a stack thickness of 0.17 mM, a size of 102461024 pixel, a line average of 2 and a scanning speed of 400 pixel/sec. Image processing concerning brightness and contrast adjustments were done using the program Image J.Luminescence Measurements and Metal TitrationsLuminescence measurements were performed using a Cary eclipse fluorescence spectrometer. Terbium (III) in complex with Zarvin was excited via energy transfer from a phenylalanine between the EF and CD metal binding sites of the Parvalbumin domain. The excitation wavelength used for this was 258 nm. Luminescence emission was detected at 543 nm (5D4 R 7F5 transition) with a delay time of 0.2 ms, a gate time of 4.5 ms and a total decay time of 200 ms. The excitation and emission slit widths used were 10 nm and 20 nm respectively. The PMT voltage was 800 V. Titrations were carried out at 20uC. Each titration step was measured in kinetic mode with an average time of 7 s over a time scale of 10 minutes. Affinity determinations of Tb3+ to the EF and CD site of the Parvalbumin domain were done in 20 mM Tris, 150 mM NaCl, pH 7.4. Each titration step was pipetted separately and all batches were incubated for three days at room temperature to establish equilibrium between the complexes Zarvin:(Tb3+)2 and NTA:Tb3+. The curve was normalised and inverted prior to fitting with a Hill equation. Using the fitted apparent affinity of NTA:Tb3+ and the real binding affinity [15] of this complex of 5.6 6 10212 M, the binding affinity of Zarvin:(Tb3+)2 was estimated according to equation: KDZarvin KDNTA : arvin Kapp {KDNTA ??Labelling of ZarvinN-terminal labelling of Zarvin as well as labelling of the cysteine residue 23977191 of Zarvin-D72C was performed using NHS-Ester and maleimide derivatives of Atto dyes respectively (Atto-tec, Siegen, Germany). Labelling was performed according to the Atto-tec protocols for amine and thiol reactive dyes respectively. The chosen labelling strategy was 1 h at room temperature and subsequent separation of the prote.
