Genome-wide analysis of major intrinsic proteins in the tree plant Populus trichocarpa: Characterization of XIP subfamily of aquaporins from evolutionary perspective

Table 8 Group conservation of small and weakly polar residues at the helix-helix interface of PtMIPs and all XIPs

Residue^a	All PtMIPs^{b, c}	Dicot XIPs^c	Fungi XIPs^c
T48	T(91), S, A *(95)*	T(86), S *(100)*	T(44), S *(67)*
T55	G(45), T(25), S, A *(80)*	T *(5)*	S(33), T, A *(67)*
A78	A(69), S, C, T *(91)*	S(73), A *(82)*	G(100) *(100)*
G82	G(51), A(41) *(91)*	A(73), S *(77)*	---
A103	A(76), S, T *(87)*	T, A *(23)*	T(44), A *(56)*
G107	G(58), A(25), S, T *(98)*	A(50), S(32) *(82)*	A(78), S *(100)*
G129	G(87), A *(100)*	G(100) *(100)*	G(100) *(100)*
A130	S(56), A(33), G, T *(100)*	A(50), G(45), S *(100)*	G(89), A *(100)*
G133	A(55), G(45) *(100)*	G(91), A *(100)*	A(89), G *(100)*
T172	T(82), G, S, A *(100)*	T(55), S(27), A *(100)*	S(33), T, A, C *(89)*
S181	A(42), S(27), G, T *(84)*	T, S *(23)*	G(100) *(100)*
G203	G(87), A, S *(100)*	G(82), A *(100)*	G(100) *(100)*
S226	S(60), A, C, T *(93)*	C(100) *(100)*	C(100) *(100)*
G248	G(73), A, C, S *(98)*	G(95) *(95)*	G(44), A(33), S *(100)*
G252	G(87), A *(98)*	A(77), S, G *(91)*	A(56), G *(78)*
A253	A(60), G, C, S, T *(98)*	C(82), S, G *(95)*	G(33), C, T, A, S *(89)*
A256	A(71), G *(87)*	---	---

^aResidue numbers correspond to that of spinach aquaporin SoPIP2;1 (PDB ID: 1Z98)
^bGroup-based conservation is reported for all the five populus MIP subfamilies based on structure-based sequence alignment of 55 Populus MIPs
^cSmall and weakly polar interfacial residues in Populus MIP sequences and their conservation (if it exceeds 25%) are given. If the conservation is less than 25%, only the residues are given. For each position, group conservation of all the five residues (Gly, Ser, Thr, Ala and Cys) is shown in bold and italics.

ISSN: 1471-2229