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3cmy
From Proteopedia
Structure of a homeodomain in complex with DNA
Structural highlights
Disease[PAX3_HUMAN] Defects in PAX3 are the cause of Waardenburg syndrome type 1 (WS1) [MIM:193500]. WS1 is an autosomal dominant disorder characterized by wide bridge of nose owing to lateral displacement of the inner canthus of each eye (dystopia canthorum), pigmentary disturbances such as frontal white blaze of hair, heterochromia of irides, white eyelashes, leukoderma and sensorineural deafness. The syndrome shows variable clinical expression and some affected individuals do not manifest hearing impairment.[1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14] [:][15] [16] Defects in PAX3 are the cause of Waardenburg syndrome type 3 (WS3) [MIM:148820]; also known as Klein-Waardenburg syndrome or Waardenburg syndrome with upper limb anomalies or white forelock with malformations. WS3 is a very rare autosomal dominant disorder, which shares many of the characteristics of WS1. Patients additionally present with musculoskeletal abnormalities. Defects in PAX3 are the cause of craniofacial-deafness-hand syndrome (CDHS) [MIM:122880]. CDHS is thought to be an autosomal dominant disease which comprises absence or hypoplasia of the nasal bones, hypoplastic maxilla, small and short nose with thin nares, limited movement of the wrist, short palpebral fissures, ulnar deviation of the fingers, hypertelorism and profound sensory-neural deafness.[17] Defects in PAX3 are a cause of rhabdomyosarcoma type 2 (RMS2) [MIM:268220]. It is a form of rhabdomyosarcoma, a highly malignant tumor of striated muscle derived from primitive mesenchimal cells and exhibiting differentiation along rhabdomyoblastic lines. Rhabdomyosarcoma is one of the most frequently occurring soft tissue sarcomas and the most common in children. It occurs in four forms: alveolar, pleomorphic, embryonal and botryoidal rhabdomyosarcomas. Note=A chromosomal aberration involving PAX3 is found in rhabdomyosarcoma. Translocation (2;13)(q35;q14) with FOXO1. The resulting protein is a transcriptional activator. Note=A chromosomal aberration involving PAX3 is a cause of rhabdomyosarcoma. Translocation t(2;2)(q35;p23) with NCOA1 generates the NCOA1-PAX3 oncogene consisting of the N-terminus part of PAX3 and the C-terminus part of NCOA1. The fusion protein acts as a transcriptional activator. Rhabdomyosarcoma is the most common soft tissue carcinoma in childhood, representing 5-8% of all malignancies in children. Function[PAX3_HUMAN] Probable transcription factor associated with development of alveolar rhabdomyosarcoma. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThe transcription regulatory protein PAX3 binds to cognate DNA sequences through two DNA-binding domains, a paired domain and a homeodomain, and has important functions during neurogenesis and myogenesis. In humans, mutations in the PAX3 gene cause Waardenburg syndrome, whereas a chromosomal translocation that generates a PAX3-FOXO1 fusion gene is associated with the development of alveolar rhabdomyosarcoma. We have determined the crystal structure of the human PAX3 homeodomain in complex with a palindromic DNA containing two inverted TAATC sequences at 1.95 A resolution. Two homeodomains bind to DNA as a symmetric dimer, inducing a 3 degrees bend in the DNA helix. The N-terminal arm of the homeodomain inserts into the minor groove and makes direct and water-mediated interactions with bases and the sugar-phosphate backbone. The recognition helix fits directly into the major groove, and an elaborate network of structurally conserved water molecules mediates the majority of protein-DNA interactions. The structure elucidates the role of serine 50 in selection of the CG sequence immediately 3' of the TAAT motif by PAX class homeodomains and provides insights into the molecular mechanisms by which certain Waardenburg syndrome-associated missense mutations could destabilize the fold of the PAX3 homeodomain whereas others could affect its interaction with DNA. Structural Basis for DNA Recognition by the Human PAX3 Homeodomain (dagger) (,) (double dagger).,Birrane G, Soni A, Ladias JA Biochemistry. 2009 Jan 21. PMID:19199574[18] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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