Table 5.
Function of the 12 domains and their constituted residues for Schistosoma mansoni protein Smp_059340.1.
| Conserved domain | Component residue(s) | Function |
|---|---|---|
| Mg2+/GTP binding site | G46, G51, K52, S53, T188, D207, G210, N276, K277, D279, C350, A351 | The Mg2+ interacts with alpha subunits of the G proteins in the present of GTP to form a complex from which nucleotide dissociate slowly |
| Adenylyl cyclase interaction site | I191, R216, I219, Q220, N223 | Stimulates the adenylyl cyclase by binding to it |
| Beta—gamma complex interaction site | S189, I191, E193, H204, F206, G210, Q211, R212, E214, K217, W218, Q220, C221, F222, N223 | The beta/gamma complex can also stimulate and inhibit the adenylyl cyclase activity, but no model of its function had been established |
| GoLoco binding site | A47, G48, E49, D77, K81, D85, C88, A91, G92, R112, I115, I156, R185, G210, W218, F222 | It binds Gαi/o/GDP complex and prevents the spontaneous release of GDP by Gα, thus acting as a guanine nucleotide dissociation inhibitor (GDI) |
| Putative receptor binding site | H342, Y343, C344, Y345, P346, H347, L348, T349, C350, A351, V352, D353, E355, N356, I357, R358 | Binds the protein to the serotonin receptor (Smp_126730) |
| Switch I region | R183, C184, R185, V186, L187, T188, S189, G190, I191 | Molecular switches (called the effector loop) |
| Switch II region | V208, G209, G210, Q211, R212, E213, E214, R215, R216, K217, W218, I219, Q220, C221, F222, N223, D224 | Molecular switches |
| G1 box motif | G46, A47, G48, E49, S50, G51, K52, S53 | GTP binding signature |
| G2 box motif | T188 | Involved in Mg2+ coordination |
| G3 box motif | D207, V208, G209, G210 | Links the subsites for binding of Mg2+ and the γ phosphate of GTP (GTP γ- phosphate- binding site) |
| G4 box motif | N276, K277, Q278, D279 | Recognizes the guanine ring |
| G5 box motif | C350, A351, V352 | Buttresses the guanine base recognition site |
Notes: In the Schistosoma mansoni protein Smp_059340.1, each of the residues contributing to the function of each domain in the complex network is presented. Most domains share residues with each other making the network very complex at atomistic level.