The CEACAM1 N-terminal Ig domain mediates cis- and trans-binding and is essential for allosteric rearrangements of CEACAM1 microclusters

Klaile, Esther; Vorontsova, Olga; Sigmundsson, Kristmundur; Müller, Mario M.; Singer, Bernhard B.; Öfverstedt, Lars-Göran; Svensson, Stina; Skoglund, Ulf; Öbrink, Björn

In all three models, the bulk analyte is referred to as A Total (given in grams/liter). The different forms of the analyte, i.e., monomer, dimer, and trimer, are referred to as [A], [A 2 ], and [A 3 ], respectively (given in micromoles/ liter). To ease the reading of the coupled differential equations applied for numerical integration (Eqs. 1.3-1.5, 2.3-2.8, and 3.6-3.15), the brackets have been dropped, and [A], [A 2 ], and [A 3 ] are provided as A, A 2 , and A 3 , respectively. Bulk concentrations of these forms are indicated with the superscript B, and unlabeled forms represent surface concentrations. Association rate constants (k a ) are given in liters/(micromoles × seconds). Dissociation rate constants (k d ) are given in the unit of seconds 1 . Under the experimental conditions (referring to a BIAcore instrument), the analyte bulk concentration is kept constant by a continuous injection at a constant flow rate. Thus, in our models, the bulk analyte forms (i.e., monomer, dimers, and trimers) are assumed to be in equilibrium.