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{{Infobox protein family
⚫
[[Image:Legume_lectin_monomer.jpg|thumb|250px|A typical legume lectin monomer ([[lentil]] lectin), complexed with a sugar ([[glucose]]). The four sugar binding loops are shown in different colors. The variable loop that confers monosaccharide specificity is shown in orange.]]
| Symbol = Lectin_legB
| Name = Legume lectin domain
| image = PDB 1lem EBI.jpg
| width =
| caption = Structure of the monosaccharide binding site of lentil lectin.<ref name="pmid7696853">{{cite journal |author=Loris R, Casset F, Bouckaert J, ''et al.'' |title=The monosaccharide binding site of lentil lectin: an X-ray and molecular modelling study |journal=Glycoconj. J. |volume=11 |issue=6 |pages=507–17 |year=1994 |month=December |pmid=7696853 |doi= |url=}}</ref>
| Pfam = PF00139The
| Pfam_clan = CL0004
| InterPro = IPR001220
| SMART =
| PROSITE = PDOC00278
| MEROPS =
| SCOP = 1lem
| TCDB =
| OPM family =
| OPM protein =
| PDB = {{PDB2|1apn}}, {{PDB2|1avb}}, {{PDB2|1ax0}}, {{PDB2|1ax1}}, {{PDB2|1ax2}}, {{PDB2|1axy}}, {{PDB2|1axz}}, {{PDB2|1azd}}, {{PDB2|1bjq}}, {{PDB2|1bqp}}, {{PDB2|1bxh}}, {{PDB2|1bzw}}, {{PDB2|1ces}}, {{PDB2|1ciw}}, {{PDB2|1cjp}}, {{PDB2|1cn1}}, {{PDB2|1con}}, {{PDB2|1cq9}}, {{PDB2|1cr7}}, {{PDB2|1cvn}}, {{PDB2|1dbn}}, {{PDB2|1dgl}}, {{PDB2|1dhk}}, {{PDB2|1dq0}}, {{PDB2|1dq1}}, {{PDB2|1dq2}}, {{PDB2|1dq4}}, {{PDB2|1dq5}}, {{PDB2|1dq6}}, {{PDB2|1dzq}}, {{PDB2|1enq}}, {{PDB2|1enr}}, {{PDB2|1ens}}, {{PDB2|1f9k}}, {{PDB2|1fat}}, {{PDB2|1fay}}, {{PDB2|1fny}}, {{PDB2|1fnz}}, {{PDB2|1fx5}}, {{PDB2|1fyu}}, {{PDB2|1g7y}}, {{PDB2|1g8w}}, {{PDB2|1g9f}}, {{PDB2|1gic}}, {{PDB2|1gkb}}, {{PDB2|1gnz}}, {{PDB2|1gsl}}, {{PDB2|1gz9}}, {{PDB2|1gzc}}, {{PDB2|1h9p}}, {{PDB2|1h9w}}, {{PDB2|1hkd}}, {{PDB2|1hql}}, {{PDB2|1hqw}}, {{PDB2|1i3h}}, {{PDB2|1ioa}}, {{PDB2|1jbc}}, {{PDB2|1jn2}}, {{PDB2|1joj}}, {{PDB2|1jui}}, {{PDB2|1jw6}}, {{PDB2|1jxn}}, {{PDB2|1jyc}}, {{PDB2|1jyi}}, {{PDB2|1lec}}, {{PDB2|1led}}, {{PDB2|1lem}}, {{PDB2|1len}}, {{PDB2|1les}}, {{PDB2|1lgb}}, {{PDB2|1lgc}}, {{PDB2|1loa}}, {{PDB2|1lob}}, {{PDB2|1loc}}, {{PDB2|1lod}}, {{PDB2|1loe}}, {{PDB2|1lof}}, {{PDB2|1log}}, {{PDB2|1lte}}, {{PDB2|1lu1}}, {{PDB2|1lu2}}, {{PDB2|1lul}}, {{PDB2|1mvq}}, {{PDB2|1n3o}}, {{PDB2|1n3p}}, {{PDB2|1n3q}}, {{PDB2|1n47}}, {{PDB2|1nls}}, {{PDB2|1nxd}}, {{PDB2|1ofs}}, {{PDB2|1ona}}, {{PDB2|1q8o}}, {{PDB2|1q8p}}, {{PDB2|1q8q}}, {{PDB2|1q8s}}, {{PDB2|1q8v}}, {{PDB2|1qdc}}, {{PDB2|1qdo}}, {{PDB2|1qf3}}, {{PDB2|1qgl}}, {{PDB2|1qmo}}, {{PDB2|1qnw}}, {{PDB2|1qny}}, {{PDB2|1qoo}}, {{PDB2|1qos}}, {{PDB2|1qot}}, {{PDB2|1rin}}, {{PDB2|1rir}}, {{PDB2|1rit}}, {{PDB2|1s1a}}, {{PDB2|1sbd}}, {{PDB2|1sbe}}, {{PDB2|1sbf}}, {{PDB2|1scr}}, {{PDB2|1scs}}, {{PDB2|1sfy}}, {{PDB2|1tei}}, {{PDB2|1ukg}}, {{PDB2|1uzy}}, {{PDB2|1uzz}}, {{PDB2|1v00}}, {{PDB2|1v6i}}, {{PDB2|1v6j}}, {{PDB2|1v6k}}, {{PDB2|1v6l}}, {{PDB2|1v6m}}, {{PDB2|1v6n}}, {{PDB2|1v6o}}, {{PDB2|1val}}, {{PDB2|1vam}}, {{PDB2|1viw}}, {{PDB2|1vln}}, {{PDB2|1wbf}}, {{PDB2|1wbl}}, {{PDB2|1wuv}}, {{PDB2|2a7a}}, {{PDB2|2ar6}}, {{PDB2|2arb}}, {{PDB2|2are}}, {{PDB2|2arx}}, {{PDB2|2auy}}, {{PDB2|2b7y}}, {{PDB2|2bqp}}, {{PDB2|2cna}}, {{PDB2|2ctv}}, {{PDB2|2cwm}}, {{PDB2|2cy6}}, {{PDB2|2cyf}}, {{PDB2|2d3p}}, {{PDB2|2d3r}}, {{PDB2|2d3s}}, {{PDB2|2d7f}}, {{PDB2|2dh1}}, {{PDB2|2dtw}}, {{PDB2|2dty}}, {{PDB2|2du0}}, {{PDB2|2du1}}, {{PDB2|2dv9}}, {{PDB2|2dva}}, {{PDB2|2dvb}}, {{PDB2|2dvd}}, {{PDB2|2dvf}}, {{PDB2|2dvg}}, {{PDB2|2e51}}, {{PDB2|2e53}}, {{PDB2|2e7q}}, {{PDB2|2e7t}}, {{PDB2|2ef6}}, {{PDB2|2eig}}, {{PDB2|2enr}}, {{PDB2|2fmd}}, {{PDB2|2g4i}}, {{PDB2|2gdf}}, {{PDB2|2gme}}, {{PDB2|2gmm}}, {{PDB2|2gmp}}, {{PDB2|2gn3}}, {{PDB2|2gn7}}, {{PDB2|2gnb}}, {{PDB2|2gnd}}, {{PDB2|2gnm}}, {{PDB2|2gnt}}, {{PDB2|2jdz}}, {{PDB2|2je7}}, {{PDB2|2je9}}, {{PDB2|2jec}}, {{PDB2|2lal}}, {{PDB2|2ltn}}, {{PDB2|2ovu}}, {{PDB2|2ow4}}, {{PDB2|2p2k}}, {{PDB2|2p34}}, {{PDB2|2p37}}, {{PDB2|2pel}}, {{PDB2|2phf}}, {{PDB2|2phr}}, {{PDB2|2pht}}, {{PDB2|2phu}}, {{PDB2|2phw}}, {{PDB2|2phx}}, {{PDB2|2sba}}, {{PDB2|2tep}}, {{PDB2|2uu8}}, {{PDB2|2zbj}}, {{PDB2|2zmk}}, {{PDB2|2zml}}, {{PDB2|2zmn}}, {{PDB2|3cna}}, {{PDB2|3d4k}}, {{PDB2|3enr}}, {{PDB2|5cna}}
}}


⚫
[[Image:Legume_lectin_monomer.jpg|thumb|170px|A typical legume lectin monomer ([[lentil]] lectin), complexed with a sugar ([[glucose]]). The four sugar binding loops are shown in different colours. The variable loop that confers monosaccharide specificity is shown in orange.]]
The '''legume lectins''' are a family of sugar binding proteins or [[lectin]]s found in the seeds and, in smaller amounts, in the roots, stems, leaves and bark of plants belonging to the [[Fabaceae]] family.<ref>Sharon, N. & Lis, H. (1990) FASEB J., 4, 3198-3208</ref><ref>Loris, R., Hamelryck, T., Bouckaert, J. & Wyns, L. (1998) Biochim.

Biophys. Acta, 1383, 9-36</ref> The exact function of the legume lectins ''in vivo'' is unknown but they are probably involved in the defense of plants against predators. Related proteins in other plant families and in animals have also been found. They have been used for decades as a model system for the study of protein-carbohydrate interactions, because they show an amazing variety of binding specificities and are easy to obtain and purify. Over the years, a
The '''legume lectins''' are a family of sugar binding proteins or [[lectin]]s found in the seeds and, in smaller amounts, in the roots, stems, leaves and bark of plants belonging to the [[Fabaceae]] family.<ref name="pmid2227211">{{cite journal |author=Sharon N, Lis H |title=Legume lectins--a large family of homologous proteins |journal=FASEB J. |volume=4 |issue=14 |pages=3198–208 |year=1990 |month=November |pmid=2227211 |doi= |url=}}</ref> <ref name="pmid9546043">{{cite journal |author=Loris R, Hamelryck T, Bouckaert J, Wyns L |title=Legume lectin structure |journal=Biochim. Biophys. Acta |volume=1383 |issue=1 |pages=9–36 |year=1998 |month=March |pmid=9546043 |doi= |url=}}</ref> The exact function of the legume lectins ''in vivo'' is unknown but they are probably involved in the defense of plants against predators. Related proteins in other plant families and in animals have also been found. They have been used for decades as a model system for the study of protein-carbohydrate interactions, because they show an amazing variety of binding specificities and are easy to obtain and purify. Over the years, a
quite impressive amount of structural data has been gathered.<ref>Loris, R., Hamelryck, T., Bouckaert, J. & Wyns, L. (1998) Biochim. Biophys. Acta, 1383, 9-36</ref> Well-studied members of this protein family include [[phytohemagglutinin]] and [[concanavalin A]].
quite impressive amount of structural data has been gathered.<ref name="pmid9546043"/> Well-studied members of this protein family include [[phytohemagglutinin]] and [[concanavalin A]].


==Sugar binding by legume lectins==
==Sugar binding by legume lectins==


The legume lectins use an ingenious framework for binding specific sugars. This framework consists of a conserved monosaccharide binding site in which four conserved residues from four separate regions in the protein confer affinity (see figure), a variable loop that confers monosaccharide
The legume lectins use an ingenious framework for binding
⚫
specificity and a number of subsites around the monosaccharide binding site that harbour additional sugar residues or hydrophobic groups. <ref name="pmid9546043"/>
specific sugars. This framework consists of a
conserved monosaccharide binding site in which four conserved residues
from four separate regions in the protein confer affinity (see figure), a variable loop that confers monosaccharide
⚫
specificity and a number of subsites around the monosaccharide binding
site that harbor additional sugar residues or hydrophobic groups<ref>Loris, R., Hamelryck, T., Bouckaert, J. & Wyns, L. (1998) Biochim. Biophys. Acta, 1383, 9-36</ref>.


⚫
==Quaternary structure==


⚫
==Quaternary structure==
⚫
The legume lectins are also interesting from the point of view of protein structure. Despite the conserved structure of the legume lectin subunit, they can adopt a wide range of quaternary structures <ref>Signature of quaternary structure in the sequences of legume lectins. (2001) N. Manoj and K. Suguna, Protein Engineering, Vol. 14, No. 10, 735-745</ref>. The reason behind this remarkable variability is to be found in the interaction with multivalent ligands.
⚫
[[Image:Legume_lectin_quat.jpg|thumb|270px|Quaternary structures of some legume lectins. One of the subunits is in the same orientation in all structures for ease of comparison.]]
⚫
The legume lectins are also interesting from the point of view of protein structure. Despite the conserved structure of the legume lectin subunit, they can adopt a wide range of quaternary structures.<ref name="pmid11739891">{{cite journal |author=Manoj N, Suguna K |title=Signature of quaternary structure in the sequences of legume lectins |journal=Protein Eng. |volume=14 |issue=10 |pages=735–45 |year=2001 |month=October |pmid=11739891 |doi= |url=}}</ref>
The reason behind this remarkable variability is to be found in the interaction with multivalent ligands.


⚫
[[Image:Legume_lectin_quat.jpg|thumb|500px|Quaternary structures of some legume lectins. One of the subunits is in the same orientation in all structures for ease of comparison.]]


==References==
==References==
{{reflist}}
<references/>


{{Lectins}}
{{Lectins}}

Revision as of 15:50, 26 August 2010

Legume lectin domain
Structure of the monosaccharide binding site of lentil lectin.[1]
Identifiers
SymbolLectin_legB
PfamPF00139The
Pfam clanCL0004
InterProIPR001220
PROSITEPDOC00278
SCOP21lem / SCOPe / SUPFAM
Available protein structures:
Pfam  structures / ECOD  
PDBRCSB PDB; PDBe; PDBj
PDBsumstructure summary
PDB1apn​, 1avb​, 1ax0​, 1ax1​, 1ax2​, 1axy​, 1axz​, 1azd​, 1bjq​, 1bqp​, 1bxh​, 1bzw​, 1ces​, 1ciw​, 1cjp​, 1cn1​, 1con​, 1cq9​, 1cr7​, 1cvn​, 1dbn​, 1dgl​, 1dhk​, 1dq0​, 1dq1​, 1dq2​, 1dq4​, 1dq5​, 1dq6​, 1dzq​, 1enq​, 1enr​, 1ens​, 1f9k​, 1fat​, 1fay​, 1fny​, 1fnz​, 1fx5​, 1fyu​, 1g7y​, 1g8w​, 1g9f​, 1gic​, 1gkb​, 1gnz​, 1gsl​, 1gz9​, 1gzc​, 1h9p​, 1h9w​, 1hkd​, 1hql​, 1hqw​, 1i3h​, 1ioa​, 1jbc​, 1jn2​, 1joj​, 1jui​, 1jw6​, 1jxn​, 1jyc​, 1jyi​, 1lec​, 1led​, 1lem​, 1len​, 1les​, 1lgb​, 1lgc​, 1loa​, 1lob​, 1loc​, 1lod​, 1loe​, 1lof​, 1log​, 1lte​, 1lu1​, 1lu2​, 1lul​, 1mvq​, 1n3o​, 1n3p​, 1n3q​, 1n47​, 1nls​, 1nxd​, 1ofs​, 1ona​, 1q8o​, 1q8p​, 1q8q​, 1q8s​, 1q8v​, 1qdc​, 1qdo​, 1qf3​, 1qgl​, 1qmo​, 1qnw​, 1qny​, 1qoo​, 1qos​, 1qot​, 1rin​, 1rir​, 1rit​, 1s1a​, 1sbd​, 1sbe​, 1sbf​, 1scr​, 1scs​, 1sfy​, 1tei​, 1ukg​, 1uzy​, 1uzz​, 1v00​, 1v6i​, 1v6j​, 1v6k​, 1v6l​, 1v6m​, 1v6n​, 1v6o​, 1val​, 1vam​, 1viw​, 1vln​, 1wbf​, 1wbl​, 1wuv​, 2a7a​, 2ar6​, 2arb​, 2are​, 2arx​, 2auy​, 2b7y​, 2bqp​, 2cna​, 2ctv​, 2cwm​, 2cy6​, 2cyf​, 2d3p​, 2d3r​, 2d3s​, 2d7f​, 2dh1​, 2dtw​, 2dty​, 2du0​, 2du1​, 2dv9​, 2dva​, 2dvb​, 2dvd​, 2dvf​, 2dvg​, 2e51​, 2e53​, 2e7q​, 2e7t​, 2ef6​, 2eig​, 2enr​, 2fmd​, 2g4i​, 2gdf​, 2gme​, 2gmm​, 2gmp​, 2gn3​, 2gn7​, 2gnb​, 2gnd​, 2gnm​, 2gnt​, 2jdz​, 2je7​, 2je9​, 2jec​, 2lal​, 2ltn​, 2ovu​, 2ow4​, 2p2k​, 2p34​, 2p37​, 2pel​, 2phf​, 2phr​, 2pht​, 2phu​, 2phw​, 2phx​, 2sba​, 2tep​, 2uu8​, 2zbj​, 2zmk​, 2zml​, 2zmn​, 3cna​, 3d4k​, 3enr​, 5cna​
A typical legume lectin monomer (lentil lectin), complexed with a sugar (glucose). The four sugar binding loops are shown in different colours. The variable loop that confers monosaccharide specificity is shown in orange.

The legume lectins are a family of sugar binding proteins or lectins found in the seeds and, in smaller amounts, in the roots, stems, leaves and bark of plants belonging to the Fabaceae family.[2] [3] The exact function of the legume lectins in vivo is unknown but they are probably involved in the defense of plants against predators. Related proteins in other plant families and in animals have also been found. They have been used for decades as a model system for the study of protein-carbohydrate interactions, because they show an amazing variety of binding specificities and are easy to obtain and purify. Over the years, a quite impressive amount of structural data has been gathered.[3] Well-studied members of this protein family include phytohemagglutinin and concanavalin A.

Sugar binding by legume lectins

The legume lectins use an ingenious framework for binding specific sugars. This framework consists of a conserved monosaccharide binding site in which four conserved residues from four separate regions in the protein confer affinity (see figure), a variable loop that confers monosaccharide specificity and a number of subsites around the monosaccharide binding site that harbour additional sugar residues or hydrophobic groups. [3]


Quaternary structure

Quaternary structures of some legume lectins. One of the subunits is in the same orientation in all structures for ease of comparison.

The legume lectins are also interesting from the point of view of protein structure. Despite the conserved structure of the legume lectin subunit, they can adopt a wide range of quaternary structures.[4] The reason behind this remarkable variability is to be found in the interaction with multivalent ligands.


References

  1. ^ Loris R, Casset F, Bouckaert J; et al. (1994). "The monosaccharide binding site of lentil lectin: an X-ray and molecular modelling study". Glycoconj. J. 11 (6): 507–17. PMID 7696853. {{cite journal}}: Explicit use of et al. in: |author= (help); Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)
  2. ^ Sharon N, Lis H (1990). "Legume lectins--a large family of homologous proteins". FASEB J. 4 (14): 3198–208. PMID 2227211. {{cite journal}}: Unknown parameter |month= ignored (help)
  3. ^ a b c Loris R, Hamelryck T, Bouckaert J, Wyns L (1998). "Legume lectin structure". Biochim. Biophys. Acta. 1383 (1): 9–36. PMID 9546043. {{cite journal}}: Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)
  4. ^ Manoj N, Suguna K (2001). "Signature of quaternary structure in the sequences of legume lectins". Protein Eng. 14 (10): 735–45. PMID 11739891. {{cite journal}}: Unknown parameter |month= ignored (help)
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