Function: Siowwei

2.1 Protein-interaction annotation: ==

Protein Functions

2.1 Protein-interaction annotation: Exploration of existing database on UnitProtKB/Swiss-Prot annotated the relationship of NUBP2 and MinD. This data similarity search detected closely related sequences from other species, and their annotation give the first clue regarding a possible function inferred from the known function of related sequences. Similar sequences originated from different species- and in an order consistent with evolutionary distance may be considered potentially orthologous.

2.2 Sequence analysis (include ClustalW- MinD & NUBP2 sequence alignment): UniProt database searches with 2ph1 (chain A) amino acid sequences indicated the sequence homology between MinD (MRP, in prokaryote) and NUBP (NBP, in eukaryote). Sequence similarity searches showed a likely relationship to the E. coli MinD gene in 48-45% of the amino acid position (Table 3). MinD gene is a membrane-associated ATPase that inhibits cell division at the poles and consequently induces normal cell division. Based on the similarity, the function of NUBP2 is predicted to involve in cell division. The remarkable alignment score illustrated the evolutionary distance between E. coli and human. Due to the similarity between NUBP2 and MinD, we favor the hypothesis that NUBP2 participates in regulating cell division and poses the characteristic of ATP-binding protein. (More explanation on Min Complex in bacteria context) Research conducted by Shahrestanifar et al. in 1994 investigated the expression of rat homolog of NUBP2 in several cell lines; it was found that NUBP2 was presence in all samples. Highest expression of NUBP2 was found in human adult’s lung, testis and skeletal tissues followed by kidney, brain, spleen and heart (Nakashima et al., 1999). Another research conducted by Unger and Hartwell in 1976 demonstrated mutation of the gene was found to be lethal, indicating the NUBP2 plays a vital role in cell division. 2.3 Sequence motif (domain) analysis: (include 3D structural analysis-active sites) Results returned from InterProScan indicate this nucleotide binding protein (NBP) shares a characteristic motif with the ATPase superfamily (Table 1). Additionally, a characteristic sequence motif “[GA]-X2-(G)-X-G-K-[ST]” called the phosphate binding group (p-loop) was identified (Table 2). Many biologically processes are thermodynamically unfavorable, and therefore cannot occur without the use of an extra source of energy. In many cases, this source of energy comes from the hydrolysis of adenosine triphosphate (ATP) molecules. Based on its ATP binding motif, this gene was called nucleotide-binding protein (NBP). Therefore, NBP is also known as ATP-binding domain. (similar motif were also found in MinD)