Spo0J (ParB)及Soj (ParA)這兩個蛋白質和parS DNA序列構成了ParAB系統並在細菌染色核質分離的過程中扮演重要的角色。它們可能藉由互相幫忙而去完成它們的任務。然而，這兩個蛋白質之間互相作用的關係及生物功能大部分都還不是很清楚。在胃幽門螺旋桿菌中，Hp1138及Hp1139這兩個蛋白質分別被預測為具有Spo0J及Soj的功能。然而，有關這兩個蛋白質的功能到目前為止都還沒有被證實。因此，這兩個蛋白質的功能，以及它們之間的互相作用是非常值得去研究的。為了要研究這兩個蛋白質的功能，重組的Hp1138及Hp1139蛋白分別被建構，純化及功能性分析。首先，這些重組蛋白質被個別研究其特性以及分析其蛋白質活性。結果顯示Hp1138具有結合parS DNA序列的能力，而Hp1139擁有水解ATP的活性。再加上在Hp1142序列中發現的兩段可能性parS DNA序列具有與Hp1138結合的能力，暗示了胃幽門螺旋桿菌中ParAB系統存在的可能性。接下來，三種不同的分法分別被運用來研究這兩個蛋白質之間的互相作用。第一，在測定水解ATP能力的實驗中，結果顯示Hp1138及parS可以促進Hp1139水解ATP的能力；更進一步地，Hp1138促進Hp1139水解ATP的能力發現在parS存在之下被增進了。第二，在研究蛋白質與核酸結合能力的實驗中，結果指出Hp1139能夠促進Hp1138結合parS DNA序列的能力，另外也發現了ATP形式的Hp1139具有parS DNA結合的能力，這與先前研究指出Soj參與Spo0J-parS複合物的形成的結果是相符合的。此外，在三種不同形式的Hp1139中，以ATP結合形式的Hp1139表現出最明顯的促進效應。另外，結果也顯示了Hp1138與ATP-Hp1139具有互相促進結合parS DNA序列的能力。以上蛋白質與核酸結合能力的實驗結果在相關研究當中是最新的發現。第三，本研究首次使用免疫共沉澱反應來研究Spo0J與Soj的相互作用，實驗結果顯示出Hp1139可以與Hp1138或Hp1138-parS作用，而其中又以與ATP結合形式的Hp1139是與Hp1138或Hp1138-parS相互作用最明顯的。然而，Hp1138與Hp1139的相互作用在胃幽門螺旋桿菌的細胞萃取物中卻沒有發現，暗示可能有更複雜的機制存在細菌體內。最後，在這個研究裡探討了胃幽門螺旋桿菌中Hp1138及Hp1139的蛋白質表現量及分布位置。酸誘導實驗結果顯示這兩個蛋白質並非酸性誘導的蛋白質。此外，它們的表現量在分裂中是較非分裂中的胃幽門螺旋桿菌多的，暗示了這兩個蛋白質可能跟細菌分裂有關。在免疫螢光顯微鏡的實驗中，可以發現到Hp1138會形成明顯分離的亮點，而此亮點的分離又與細菌核核質的分離總是一起的；另外Hp1139被發現在細菌分裂過程中會形成類似螺旋狀的結構。上述發現都與先前對Spo0J與Soj的分布研究都相當符合。所以從以上的結果可以猜測Hp1138與Hp1139可能與胃幽門螺旋桿菌的染色核質分離相當有關。然而，Hp1138及Hp1139在胃幽門螺旋桿菌中的真實生物功能需要更進一步的實驗去證實。

Spo0J (ParB), Soj (ParA) proteins and parS DNA sequence were ParAB system implicated in bacterial chromosome segregation. They may work together to accomplish their functions. However, the interaction-relationship and bio-functions between Spo0J and Soj remained largely unclear. In H. pylori, Hp1138 and Hp1139 was putative Spo0J and Soj protein, respectively. However, there were no published data to support their functions. Therefore, it was worth investigating the functions and studying the interactions between these two proteins. To study their functions, recombinant Hp1138 and Hp1139 were constructed, purified and assayed. And high sensitivity and specificity antibodies were prepared. First, the recombinant proteins were characterized and assayed for their individual activity. The data showed that Hp1138 had parS-binding activity and Hp1139 possessed ATPase activity. Together with the possible parS sequences in Hp1142 were found to have binding activity to Hp1138, suggesting ParAB system might exist in H. pylori. Next, three methods were applied to study the interactions between Hp1138, parS and Hp1139. First, ATPase assay indicated that Hp1138 and parS could activate the activity of Hp1139. In addition, the activation by Hp1138 was enhanced in the presence of parS. Second, agarose EMSA showed that Hp1139 could improve parS-binding of Hp1138 and ATP-bound Hp1139 had low parS-binding activity, consistent with that Soj was reported to play a role in the formation of Spo0J-parS complex. Among three states, the ATP-bound Hp1139 was the most efficient effecter. Furthermore, ATP-Hp1139 and Hp1138 could improve parS-binding of each other. The above mentioned agarose EMSA data were new findings in related studies. Third, in Co-IP, the data revealed that Hp1139 could interact with Hp1138 or Hp1138-parS, again the ATP-bound Hp1139 was the most significant interaction partner. However, interaction between Hp1138 and Hp1139 was not found in H. pylori lysate, indicating that a more complicated mechanism might exist in vivo. Finally, protein level and localization of Hp1138 and Hp1139 in H. pylori was determined. Acid-induced analysis showed that these two proteins were not acid-induced protein. Their expression in dividing H. pylori were more than non-dividing H. pylori, suggesting that these two proteins might be involved in cell division. The immuno-fluorescence images displayed that Hp1138 formed discrete foci co-separated with nucleoid and Hp1139 formed helix-like structure through cell division, consistent with previous studies on localization of Spo0J and Soj. The above results suggested that Hp1138 and Hp1139 may be involved in chromosome segregation in H. pylori. However, further experiments were required for studying the bio-functions of Hp1138 and Hp1139 in vivo.

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