View source for 1r14

[[Image:1r14.jpg|left|200px]]<br /><applet load="1r14" size="350" color="white" frame="true" align="right" spinBox="true" 
caption="1r14, resolution 2.5&Aring;" />
'''Carbohydrate recognition and neck domains of surfactant protein A (Sp-A) containing samarium'''<br />

==Overview==
Surfactant protein A (SP-A), one of four proteins associated with pulmonary surfactant, binds with high affinity to alveolar phospholipid membranes, positioning the protein at the first line of defense against inhaled pathogens. SP-A exhibits both calcium-dependent carbohydrate binding, a characteristic of the collectin family, and specific interactions with lipid membrane components. The crystal structure of the trimeric carbohydrate recognition domain and neck domain of SP-A was solved to 2.1-A resolution with multiwavelength anomalous dispersion phasing from samarium. Two metal binding sites were identified, one in the highly conserved lectin site and the other 8.5 A away. The interdomain carbohydrate recognition domain-neck angle is significantly less in SP-A than in the homologous collectins, surfactant protein D, and mannose-binding protein. This conformational difference may endow the SP-A trimer with a more extensive hydrophobic surface capable of binding lipophilic membrane components. The appearance of this surface suggests a putative binding region for membrane-derived SP-A ligands such as phosphatidylcholine and lipid A, the endotoxic lipid component of bacterial lipopolysaccharide that mediates the potentially lethal effects of Gram-negative bacterial infection.

==About this Structure==
1R14 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Rattus_norvegicus Rattus norvegicus] with <scene name='pdbligand=SM:'>SM</scene> and <scene name='pdbligand=MES:'>MES</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1R14 OCA]. 

==Reference==
Crystal structure of trimeric carbohydrate recognition and neck domains of surfactant protein A., Head JF, Mealy TR, McCormack FX, Seaton BA, J Biol Chem. 2003 Oct 31;278(44):43254-60. Epub 2003 Aug 11. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=12913002 12913002]
[[Category: Rattus norvegicus]]
[[Category: Single protein]]
[[Category: Head, J F.]]
[[Category: McCormack, F X.]]
[[Category: Mealy, T R.]]
[[Category: Seaton, B A.]]
[[Category: MES]]
[[Category: SM]]
[[Category: alpha helical neck region]]
[[Category: crd]]

''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 14:45:51 2008''