Alteration in glycerol and metalloid permeability by a single mutation in the extracellular C-loop of Leishmania major aquaglyceroporin LmAQP1.
نویسندگان
چکیده
The Leishmania major aquaglyceroporin, LmAQP1, is responsible for the transport of antimonite [Sb(III)], an activated form of Pentostam or Glucantime. Downregulation of LmAQP1 provides resistance to trivalent antimony compounds and increased expression of LmAQP1 in drug-resistant parasites can reverse the resistance. Besides metalloid transport, LmAQP1 is also permeable to water, glycerol, methylglyoxal, dihydroxyacetone and sugar alcohols. LmAQP1 also plays a physiological role in volume regulation and osmotaxis. In this study, we examined the role of extracellular C-loop glutamates (Glu143, Glu145 and Glu152) in LmAQP1 activity. Alteration of both Glu143 and Glu145 to alanines did not affect either the biochemical or physiological properties of the protein, suggesting that neither residue is critical for LmAQP1 activity. Alteration of Glu152 to alanine, aspartate and glutamine affected metalloid transport in the order, wild-type > E152Q > E152D > E152A. In fact, axenic amastigotes expressing E152A LmAQP1 accumulated negligible levels of either arsenite [As(III)] or Sb(III). Alteration of Glu152 significantly affected volume regulation and osmotaxis, suggesting that Glu152 is critical for the physiological activity of the parasite. More importantly, alteration of Glu152 to alanine did not affect glycerol permeability. Although the metalloids, As(III) and Sb(III), are believed to be transported through aquaglyceroporin channels as they behave as inorganic molecular mimic of glycerol, this is the first report where metalloid and glycerol transport can be dissected by a single mutation at the extracellular pore entry of LmAQP1 channel.
منابع مشابه
The role of alanine 163 in solute permeability of Leishmania major aquaglyceroporin LmAQP1.
Leishmania major aquaglyceroporin LmAQP1 allows adventitious passage of antimonite, an activated form of the drug Pentostam, which is used as the first line treatment for leishmaniasis. The extracellular C-loop of an aquaglyceroporin confers substrate specificity. Alteration of Glu125 to serine in the Plasmodium falciparum aquaglyceroporin PfAQP has been shown to selectively affect water but no...
متن کاملDrug uptake and modulation of drug resistance in Leishmania by an aquaglyceroporin.
Leishmaniasis is a protozoan parasitic disease that affects 12 million people worldwide. The first line choice for the treatment of this disease is antimonial drugs. In the endemic regions, resistance to this class of drugs is a major impediment to treatment. Microbes often become resistant to drugs by mutation or down-regulation of uptake systems, but the uptake system for the antimonial drugs...
متن کاملMolecular dissection of water and glycerol permeability of the aquaglyceroporin from Plasmodium falciparum by mutational analysis.
The selectivity of aquaporins for water and solutes is determined by pore diameter. Paradoxically, the wider pores of glycerol facilitators restrict water passage by an unknown mechanism. Earlier we characterized an aquaglyceroporin from Plasmodium falciparum with high permeability for both glycerol and water. We use point mutations to demonstrate that amino acids directly lining the pore are n...
متن کاملPentostam activation and uptake in Leishmania major: Role of the Sb(V) reductase LmAcr2 and the aquaglyceroporin LmAqp1
متن کامل
تأثیر محلول‌های نگه‌دارنده‌ی مختلف در فرایند انجماد بر عفونت‌زایی لیشمانیاماژور در مدل موشی
Background and Aim: Leishmanization (LZ) is an effective tool to prevent cutaneous leishmaniasis. Standardization of Leishmania is the main drawback of LZ. The aim of this study was to assess the effect of various preservatives on the infectivity of Leishmania.Methods: L.major harvested at different stages of growth logarithmic, early and late stationary phases were frozen using various pr...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- Molecular microbiology
دوره 70 6 شماره
صفحات -
تاریخ انتشار 2008