SPXX, a frequent sequence motif in gene regulatory proteins

摘要: A new DNA-binding unit, composed of four amino acid residues and common in gene regulatory proteins, is proposed. The occurrences the sequences Ser-Pro-X-X (SPXX) Thr-Pro-X-X (TPXX) proteins are compared with those general proteins. These found more frequently including homoeotic products, segmentation steroid hormone receptors certain oncogene than they that not directly involved regulation, such as core histones, or It therefore suggested these contribute to a manner important for regulation. Amino characteristic types variable X: basic residues, Lys Arg, H1 sea urchin spermatogenous H2B; Tyr RNA polymerase II; Ser, Thr, Ala, Leu Pro other S(T)PXX located on either side DNA-recognizing units Zn fingers, helix-turn-helices, cores histones. structure sequence presumed be beta-turn I stabilized by two hydrogen bonds, its potential mode discussed.