View source for 1hgj

[[Image:1hgj.gif|left|200px]]<br />
<applet load="1hgj" size="450" color="white" frame="true" align="right" spinBox="true" 
caption="1hgj, resolution 2.7&Aring;" />
'''BINDING OF INFLUENZA VIRUS HEMAGGLUTININ TO ANALOGS OF ITS CELL-SURFACE RECEPTOR, SIALIC ACID: ANALYSIS BY PROTON NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY AND X-RAY CRYSTALLOGRAPHY'''<br />

==Overview==
The interaction between influenza virus hemagglutinin and its cell-surface, receptor, 5-N-acetylneuraminic acid (sialic acid), was probed by the, synthesis of 12 sialic acid analogs, including derivatives at the, 2-carboxylate, 5-acetamido, 4-, 7-, and 9-hydroxyl, and glycosidic, positions. The equilibrium dissociation constants of these analogs were, determined by nuclear magnetic resonance spectroscopy. Ligand, modifications that reduced or abolished binding included the replacement, of the 2-carboxylate with a carboxamide, the substitution of azido or, N-benzyloxycarbonyl groups for the 5-acetamido group, and the replacement, of the 9-hydroxyl with amino or O-acetyl moieties. Modifications having, little effect on binding included the introduction of longer chains at the, 4-hydroxyl position, the replacement of the acetamido methyl group with an, ethyl group, and the removal of the 7-hydroxyl group. X-ray diffraction, studies yielded 3 A resolution crystal structures of hemagglutinin in, complex with four of the synthetic analogs [alpha-2-O-methyl-, 4-O-acetyl-alpha-2-O-methyl-, 9-amino-9-deoxy-alpha-2-O-methyl-, and, alpha-2-O-(4'-benzylamidocarboxybutyl)-N-acetylneuraminic acid] and with, the naturally occurring cell-surface saccharide (alpha 2-3)sialyllactose., The X-ray studies unambiguously establish the position and orientation of, bound sialic acid, indicate the position of the lactose group of (alpha, 2-3)sialyllactose, and suggest the location of an alpha-glycosidic chain, (4'-benzylamidocarboxybutyl) that increases the binding affinity of sialic, acid by a factor of about 3. Although the protein complexed with, alpha-2-O-methylsialic acid contains the mutation Gly-135--&gt;Arg near the, ligand binding site, the mutation apparently does not affect the ligand's, position. The X-ray studies allow us to interpret the binding affinities, in terms of the crystallographic structure. The results suggest further, experiments which could lead to the design of tight binding inhibitors of, possible therapeutic value.

==About this Structure==
1HGJ is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Unidentified_influenza_virus Unidentified influenza virus] with NAG and AMN as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1HGJ OCA]. 

==Reference==
Binding of influenza virus hemagglutinin to analogs of its cell-surface receptor, sialic acid: analysis by proton nuclear magnetic resonance spectroscopy and X-ray crystallography., Sauter NK, Hanson JE, Glick GD, Brown JH, Crowther RL, Park SJ, Skehel JJ, Wiley DC, Biochemistry. 1992 Oct 13;31(40):9609-21. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=1327122 1327122]
[[Category: Single protein]]
[[Category: Unidentified influenza virus]]
[[Category: Brown, J.H.]]
[[Category: Crowther, R.L.]]
[[Category: Glick, G.D.]]
[[Category: Hanson, J.E.]]
[[Category: Park, S.J.]]
[[Category: Sauter, N.K.]]
[[Category: Skehel, J.J.]]
[[Category: Wiley, D.C.]]
[[Category: AMN]]
[[Category: NAG]]
[[Category: influenza virus hemagglutinin]]

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