Table 1 Mutation design by alanine scanning

Oxygen-containing residues expected to engage in co-ordination of the calcium ion (denoted x, y, z, −x, −z by convention) were replaced systematically by an alanine residue.

Dockerinxyz−x−zxyz−x−z
Wild-typeDocSDNDNDDNDND
Single mutationA1ANDNDDNDND
A2DADNDDNDND
A3DNANDDNDND
A4DNDADDNDND
A5DNDNADNDND
A6DNDNDANDND
A7DNDNDDADND
A8DNDNDDNAND
A9DNDNDDNDAD
A10DNDNDDNDNA
Double mutations in one calcium-binding loopB1ANDNADNDND
B2DNDNDANDNA
Double mutations: one mutation in each calcium-binding loopC1ANDNDANDND
C2DADNDDADND
C3DNANDDNAND
C4DNDADDNDAD
C5DNDNADNDNA