Question

Across the different types of catalytic families, the position of the two domains with respect to one another varied, but only within a range of about ______

(a) 20°

(b) 10°

(c) 90°

(d) 80°

I had been asked this question in an interview.

This key question is from Structural Analyses of Domain Interactions topic in chapter Global Approaches for Studying Protein – Protein Interactions of Bioinformatics

Answer 1

The correct option is (c) 90°

The best explanation: This is the result of a functional constraint in these enzymes: the catalytic domain can only take up a variety of positions, as the substrate needs to be held sufficiently close to the NAD(P) cofactor of the Rossmann domain. In other multidomain proteins where there is no such strict functional constraint, the domain interfaces of one domain family to other families may well be more variable.