Lüleyap H Umit, Alptekin Davut, Pazarbaşi Ayfer, Kasap Mulkiye, Kasap Halil, Demirhindi Hakan, Mungan Neslihan, Ozer Güler, Froster Ursula G
University of Cukurova, Faculty of Medicine, Department of Medical Biology and Genetics, Adana, Turkey.
Mutat Res. 2006 Oct 10;601(1-2):39-45. doi: 10.1016/j.mrfmmm.2006.05.006. Epub 2006 Jun 12.
Phenylalanine hydroxylase (PAH) gene mutations were investigated in 23 (46 alleles) unrelated phenylketonuria (PKU) patients in Cukurova region. First, all exons of PAH gene were screened by denaturing high performance liquid chromatography (DHPLC), and then, the suspicious samples were analyzed by direct sequencing technique. Consequently, the following results were obtained: IVS10-11g-->a splicing mutation in 27/46 (58.7%), R261Q mutation in 7/46 (15.2%) and E178G, R243X, R243Q, P281L, Y386C, R408W mutations, each found in the frequency of 2/46 (4.3%). In many countries, Arginine mutations have the highest frequency among PAH gene mutations in PKU patients. Although, CpG dinucleotids are effective in mutations resulting in arginine changes, this finding originated from the studies on the causes of mutations rather than the studies on the importance of arginine amino acid. In our analyses, we have detected that a majority of mutations causing a change in arginine and other amino acids concentrated in exon 7 comprising the catalytic domain (residues 143-410) of PAH gene. Several studies has emphasized the role of arginine amino acid; with the following outcomes; arginine repetition is significant for RNA binding proteins, and for histon proteins in eukaryotic gene expression, and also arginine repetition occurring in the structure of signal recognition particle's (SRPs) as a consequence of post-translational processes is very important in terms of gene expression. Therefore, the role of arginine amino acid in PAH gene is rather remarkable in that it shows the role of amino acids in the protein/RNA interaction that has started in the evolutionary process and is still preserved and maintained in the motif formation of active domain structure due to its strong binding properties. Thus, such properties imply that both arginine amino acid and exon 7 is of great significance with regards to the structure and function of the PheOH enzyme.
对库库洛瓦地区23名（46个等位基因）非亲缘关系的苯丙酮尿症（PKU）患者的苯丙氨酸羟化酶（PAH）基因突变进行了研究。首先，通过变性高效液相色谱（DHPLC）筛选PAH基因的所有外显子，然后，对可疑样本采用直接测序技术进行分析。结果如下：27/46（58.7%）存在IVS10 - 11g→a剪接突变，7/46（15.2%）存在R261Q突变，E178G、R243X、R243Q、P281L、Y386C、R408W突变的频率均为2/46（4.3%）。在许多国家，精氨酸突变在PKU患者的PAH基因突变中频率最高。虽然，CpG二核苷酸在导致精氨酸变化的突变中起作用，但这一发现源于对突变原因的研究，而非对精氨酸氨基酸重要性的研究。在我们的分析中，我们检测到导致精氨酸和其他氨基酸变化的大多数突变集中在PAH基因包含催化结构域（第143 - 410位氨基酸）的外显子7中。多项研究强调了精氨酸氨基酸的作用，结果如下：精氨酸重复对于RNA结合蛋白以及真核基因表达中的组蛋白很重要，并且由于翻译后过程在信号识别颗粒（SRP）结构中发生的精氨酸重复在基因表达方面也非常重要。因此，精氨酸氨基酸在PAH基因中的作用相当显著，因为它显示了氨基酸在蛋白质/RNA相互作用中的作用，这种相互作用始于进化过程，并因其强大的结合特性在活性结构域结构的基序形成中仍然得以保留和维持。因此，这些特性意味着精氨酸氨基酸和外显子7对于苯丙氨酸羟化酶（PheOH）的结构和功能都具有重要意义。
