Structure of PDB 2bb5 Chain A

Receptor sequence

>2bb5A (length=409) Species: 9606 (Homo sapiens)

EMCEIPEMDSHLVEKLGQHLLPWMDRLSLEHLNPSIYVGLRLSSLQAGTK
EDLYLHSLKLGYQQCLLGSAFSEDDGDCQGKPSMGQLALYLLALRANCEF
VRGHKGDRLVSQLKWFLEDEKRAIGHDHKGHPHTSYYQYGLGILALCLHQ
KRVHDSVVDKLLYAVEPFHQGHHSVDTAAMAGLAFTCLKRSNFNPGRRQR
ITMAIRTVREEILKAQTPEGHFGNVYSTPLALQFLMTSPMPGAELGTACL
KARVALLASLQDGAFQNALMISQLLPVLNHKTYIDLIFPDCLAPRVMLEP
AAETIPQTQEIISVTLQVLSLLPPYRQSISVLAGSTVEDVLKKAHELGGF
TYETQASLSGPYLTSVMGKAAGEREFWQLLRDPNTPLLQGIADYRPKDGE
TIELRLVSW

3D structure

• PDB: 2bb5 Structural basis for mammalian vitamin B12 transport by transcobalamin.
• Chain: A
• Resolution: 3.2 Å

Interaction with ligand

Site #	Ligand	Ligand chain	Binding residues on receptor (original residue number in PDB)	Binding residues on receptor (residue number reindexed from 1)	Binding affinity
BS01	B12	A	G85 Q86 T134 Y137 Q138 H172 H173 D176 N224 Y226 S227 M270 S357 L358 S359 G360 Y362 L363 F376 W377 Q378 L379 L387 L388 G390 W409	G85 Q86 T134 Y137 Q138 H172 H173 D176 N224 Y226 S227 M270 S357 L358 S359 G360 Y362 L363 F376 W377 Q378 L379 L387 L388 G390 W409

Gene Ontology

Molecular Function

• GO:0005515 protein binding
• GO:0031419 cobalamin binding
• GO:0046872 metal ion binding
• GO:0140355 cargo receptor ligand activity

Biological Process

• GO:0006824 cobalt ion transport
• GO:0015889 cobalamin transport

Cellular Component

• GO:0005576 extracellular region
• GO:0005615 extracellular space
• GO:0005886 plasma membrane
• GO:0009897 external side of plasma membrane
• GO:0043202 lysosomal lumen

External links

• PDB: RCSB:2bb5, PDBe:2bb5, PDBj:2bb5
• PDBsum: 2bb5
• PubMed: 16537422
• UniProt: P20062|TCO2_HUMAN Transcobalamin-2 (Gene Name=TCN2)