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5e6v
From Proteopedia
Re-refinement of the Crystal Structure of the Plexin-Semaphorin-Integrin Domain/Hybrid Domain/I-EGF1 Segment from the Human Integrin b2 Subunit
Structural highlights
DiseaseITB2_HUMAN Defects in ITGB2 are the cause of leukocyte adhesion deficiency type 1 (LAD1) [MIM:116920. LAD1 patients have recurrent bacterial infections and their leukocytes are deficient in a wide range of adhesion-dependent functions.[1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] FunctionITB2_HUMAN Integrin alpha-L/beta-2 is a receptor for ICAM1, ICAM2, ICAM3 and ICAM4. Integrins alpha-M/beta-2 and alpha-X/beta-2 are receptors for the iC3b fragment of the third complement component and for fibrinogen. Integrin alpha-X/beta-2 recognizes the sequence G-P-R in fibrinogen alpha-chain. Integrin alpha-M/beta-2 recognizes P1 and P2 peptides of fibrinogen gamma chain. Integrin alpha-M/beta-2 is also a receptor for factor X. Integrin alpha-D/beta-2 is a receptor for ICAM3 and VCAM1. Triggers neutrophil transmigration during lung injury through PTK2B/PYK2-mediated activation.[12] Publication Abstract from PubMedHigh-resolution crystal structures of the headpiece of lymphocyte function-associated antigen-1 (integrin alphaLbeta2) reveal how the alphaI domain interacts with its platform formed by the alpha-subunit beta-propeller and beta-subunit betaI domains. The alphaLbeta2 structures compared with alphaXbeta2 structures show that the alphaI domain, tethered through its N-linker and a disulfide to a stable beta-ribbon pillar near the center of the platform, can undergo remarkable pivoting and tilting motions that appear buffered by N-glycan decorations that differ between alphaL and alphaX subunits. Rerefined beta2 integrin structures reveal details including pyroglutamic acid at the beta2 N terminus and bending within the EGF1 domain. Allostery is relayed to the alphaI domain by an internal ligand that binds to a pocket at the interface between the beta-propeller and betaI domains. Marked differences between the alphaL and alphaX subunit beta-propeller domains concentrate near the binding pocket and alphaI domain interfaces. Remarkably, movement in allostery in the betaI domain of specificity determining loop 1 (SDL1) causes concerted movement of SDL2 and thereby tightens the binding pocket for the internal ligand. Leukocyte integrin alphaLbeta2 headpiece structures: The alphaI domain, the pocket for the internal ligand, and concerted movements of its loops.,Sen M, Springer TA Proc Natl Acad Sci U S A. 2016 Mar 15;113(11):2940-5. doi:, 10.1073/pnas.1601379113. Epub 2016 Mar 2. PMID:26936951[13] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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