Molecular dynamics study of the archaeal aquaporin AqpM

BMC Genomics

Proceedings

Raul Araya-Secchi¹  Tomas Perez-Acle²  JA Garate³  David S Holmes⁴ 

[1] Computational Biology Laboratory, Centro de Modelamiento Matematico, Facultad de Ciencias Fisicas y Matematicas, Universidad de Chile, Santiago, Chile;Facultad de Ciencias Biologicas, Universidad Andres Bello, Santiago, Chile;Computational Biology Laboratory, Centro de Modelamiento Matematico, Facultad de Ciencias Fisicas y Matematicas, Universidad de Chile, Santiago, Chile;Fundacion Ciencia para la Vida, Santiago, Chile;Computational Biology Laboratory, Centro de Modelamiento Matematico, Facultad de Ciencias Fisicas y Matematicas, Universidad de Chile, Santiago, Chile;School of Chemical and Bioprocess Engineering, University College Dublin, Dublin 4, Ireland;Facultad de Ciencias Biologicas, Universidad Andres Bello, Santiago, Chile;Fundacion Ciencia para la Vida, Santiago, Chile;

关键词: Molecular Dynamic Simulation;    Water Permeability;    Selectivity Filter;    Channel Axis;    Permeability Constant;   

DOI  :  10.1186/1471-2164-12-S4-S8

来源: Springer

【 摘 要 】

BackgroundAquaporins are a large family of transmembrane channel proteins that are present throughout all domains of life and are implicated in human disorders. These channels, allow the passive but selective movement of water and other small neutral solutes across cell membranes. Aquaporins have been classified into two sub-families: i) strict aquaporins that only allow the passage of water and ii) the less selective aquaglyceroporins that transport water and other neutral solutes, such as glycerol, CO2 or urea. Recently, the identification and characterization of a number of archaeal and bacterial aquaporins suggested the existence of a third sub-family; one that is neither a strict aquaporin nor an aquaglyceroporin. The function and phylogeny of this third family is still a matter of debate.ResultsTwenty nanosecond molecular dynamics (MD) simulation of a fully hydrated tetramer of AqpM embedded in a lipid bilayer permitted predictions to be made of key biophysical parameters including: single channel osmotic permeability constant (pf), single channel diffusive permeability constant (pd), channel radius, potential water occupancy of the channel and water orientation inside the pore. These properties were compared with those of well characterized representatives of the two main aquaporin sub-families. Results show that changes in the amino acid composition of the aromatic/arginine region affect the size and polarity of the selectivity filter (SF) and could help explain the difference in water permeability between aquaporins. In addition, MD simulation results suggest that AqpM combines characteristics of strict aquaporins, such as the narrow SF and channel radius, with those of aquaglyceroporins, such as a more hydrophobic and less polar SF.ConclusionsMD simulations of AqpM extend previous evidence that this archaeal aquaporin exhibits hybrid features intermediate between the two known aquaporin sub-families, supporting the idea that it may constitute a member of a novel class of aquaporins.

【 授权许可】

CC BY   
© Araya-Secchi et al; licensee BioMed Central Ltd. 2011