A new subfamily of major intrinsic proteins in plants.

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A new subfamily of major intrinsic proteins in plants. / Johanson, Urban; Gustavsson, Sofia.

I: Molecular biology and evolution, Vol. 19, Nr. 4, 2002, s. 456-461.

Forskningsoutput: TidskriftsbidragArtikel i vetenskaplig tidskrift

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TY - JOUR

T1 - A new subfamily of major intrinsic proteins in plants.

AU - Johanson, Urban

AU - Gustavsson, Sofia

PY - 2002

Y1 - 2002

N2 - The major intrinsic proteins (MIPs) form a large protein family of ancient origin and are found in bacteria, fungi, animals, and plants. MIPs act as channels in membranes to facilitate passive transport across the membrane. Some MIPs allow small polar molecules like glycerol or urea to pass through the membrane. However, the majority of MIPs are thought to be aquaporins (AQPs), i.e., they are specific for water transport. Plant MIPs can be subdivided into the plasma membrane intrinsic protein, tonoplast intrinsic protein, and NOD26-like intrinsic protein subfamilies. By database mining and phylogenetic analyses, we have identified a new subfamily in plants, the Small basic Intrinsic Proteins (SIPs). Comparisons of sequences from the new subfamily with conserved amino acid residues in other MIPs reveal characteristic features of SIPs. Possible functional consequences of these features are discussed in relation to the recently solved structures of AQP1 and GlpF. We suggest that substitutions at conserved and structurally important positions imply a different substrate specificity for the new subfamily.

AB - The major intrinsic proteins (MIPs) form a large protein family of ancient origin and are found in bacteria, fungi, animals, and plants. MIPs act as channels in membranes to facilitate passive transport across the membrane. Some MIPs allow small polar molecules like glycerol or urea to pass through the membrane. However, the majority of MIPs are thought to be aquaporins (AQPs), i.e., they are specific for water transport. Plant MIPs can be subdivided into the plasma membrane intrinsic protein, tonoplast intrinsic protein, and NOD26-like intrinsic protein subfamilies. By database mining and phylogenetic analyses, we have identified a new subfamily in plants, the Small basic Intrinsic Proteins (SIPs). Comparisons of sequences from the new subfamily with conserved amino acid residues in other MIPs reveal characteristic features of SIPs. Possible functional consequences of these features are discussed in relation to the recently solved structures of AQP1 and GlpF. We suggest that substitutions at conserved and structurally important positions imply a different substrate specificity for the new subfamily.

KW - Algorithms

KW - Amino Acid Sequence

KW - Comparative Study

KW - Expressed Sequence Tags

KW - Gene Expression Profiling

KW - Genes

KW - Plant

KW - Ion Channels : genetics

KW - Molecular Sequence Data

KW - Phylogeny

KW - Species Specificity

KW - Amino Acid

KW - Sequence Homology

KW - Plant Proteins : genetics

M3 - Article

VL - 19

SP - 456

EP - 461

JO - Molecular biology and evolution

JF - Molecular biology and evolution

SN - 0737-4038

IS - 4

ER -