2v8n: Difference between revisions

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==Overview==

Here we describe an x-ray structure of wild-type lactose permease (LacY), from Escherichia coli determined by manipulating phospholipid content, during crystallization. The structure exhibits the same global fold as the, previous x-ray structures of a mutant that binds sugar but cannot catalyze, translocation across the membrane. LacY is organized into two six-helix, bundles with twofold pseudosymmetry separated by a large interior, hydrophilic cavity open only to the cytoplasmic side and containing the, side chains important for sugar and H(+) binding. To initiate transport, binding of sugar and/or an H(+) electrochemical gradient increases the, probability of opening on the periplasmic side. Because the inward-facing, conformation represents the lowest free-energy state, the rate-limiting, step for transport may be the conformational change leading to the, outward-facing conformation.

Here we describe an x-ray structure of wild-type lactose permease (LacY) from Escherichia coli determined by manipulating phospholipid content during crystallization. The structure exhibits the same global fold as the previous x-ray structures of a mutant that binds sugar but cannot catalyze translocation across the membrane. LacY is organized into two six-helix bundles with twofold pseudosymmetry separated by a large interior hydrophilic cavity open only to the cytoplasmic side and containing the side chains important for sugar and H(+) binding. To initiate transport, binding of sugar and/or an H(+) electrochemical gradient increases the probability of opening on the periplasmic side. Because the inward-facing conformation represents the lowest free-energy state, the rate-limiting step for transport may be the conformational change leading to the outward-facing conformation.

==About this Structure==

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[[Category: Guan, L.]]

[[Category: Iwata, S.]]

[[Category: Kaback, H.R.]]

[[Category: Kaback, H R.]]

[[Category: Mirza, O.]]

[[Category: Verner, G.]]

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[[Category: transport protein]]

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''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 18:54:06 2008''

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@@ Line 4: / Line 4: @@
 ==Overview==
-Here we describe an x-ray structure of wild-type lactose permease (LacY), from Escherichia coli determined by manipulating phospholipid content, during crystallization. The structure exhibits the same global fold as the, previous x-ray structures of a mutant that binds sugar but cannot catalyze, translocation across the membrane. LacY is organized into two six-helix, bundles with twofold pseudosymmetry separated by a large interior, hydrophilic cavity open only to the cytoplasmic side and containing the, side chains important for sugar and H(+) binding. To initiate transport, binding of sugar and/or an H(+) electrochemical gradient increases the, probability of opening on the periplasmic side. Because the inward-facing, conformation represents the lowest free-energy state, the rate-limiting, step for transport may be the conformational change leading to the, outward-facing conformation.
+Here we describe an x-ray structure of wild-type lactose permease (LacY) from Escherichia coli determined by manipulating phospholipid content during crystallization. The structure exhibits the same global fold as the previous x-ray structures of a mutant that binds sugar but cannot catalyze translocation across the membrane. LacY is organized into two six-helix bundles with twofold pseudosymmetry separated by a large interior hydrophilic cavity open only to the cytoplasmic side and containing the side chains important for sugar and H(+) binding. To initiate transport, binding of sugar and/or an H(+) electrochemical gradient increases the probability of opening on the periplasmic side. Because the inward-facing conformation represents the lowest free-energy state, the rate-limiting step for transport may be the conformational change leading to the outward-facing conformation.
 ==About this Structure==
@@ Line 15: / Line 15: @@
 [[Category: Guan, L.]]
 [[Category: Iwata, S.]]
-[[Category: Kaback, H.R.]]
+[[Category: Kaback, H R.]]
 [[Category: Mirza, O.]]
 [[Category: Verner, G.]]
@@ Line 27: / Line 27: @@
 [[Category: transport protein]]
-''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Wed Jan 23 12:58:51 2008''
+''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 18:54:06 2008''