Читать книгу The Internet of Medical Things (IoMT) - Группа авторов - Страница 22

The isoelectric point (pI) value quantified for EFGR (pI > 7) specify basic feature while the pI for k-ras and TP53 (pI < 7) exhibit acidic. Besides that, the molecular weight of EFGR, k-ras oncogene protein, and TP53 are 50,343.70, 21,470.62, and 38,532.60 Daltons, respectively. The extent of light being by absorbed by protein at a specific wavelength was used to calculate the extinction coefficient of TYR, TRP, and CYS residues where for EGFR is 38,305 M/cm, k-ras oncogene protein is 12,170M/cm, and TP53 is 43,025 M/cm. In addition, –R is the negatively (ASP + GLU) and +R is the positively charged (ARG + LYS) residues in the amino acid sequence. The total of –R and +R for each protein model was described in Table 1.1. According to the instability index of ExPASy ProtParam, EGFR proteins are classified as stable because the instability index for both proteins are less than 40 while K-ras oncogene protein and TP53 is categorized as unstable as the instability index is more than 40. The instability index for EGFR is 35.56, K-ras oncogene protein is 43.95, and TP53 is 80.17. On top of that, the very low grand average of hydropathicity (GRAVY) index (a (negative value GRAVY) of EGFR, K-ras oncogene protein, and TP53 denotes their hydrophilic nature (Table 1.1). Apart from that, EFGR, K-ras and TP53 have more polar residues (41.52%, 53.33%, and 45.29%) than non-polar residues (26.74%, 30.0%, and 27.35%) which were determined using Color Protein Sequence.

Table 1.1 Physiochemical characters of EGFR, K-ras, and TP53 proteins as determined by ExPASy ProtParam program.

Protein	Length	Molecular weight (kDa)	Pl	–R	+R	Extinction coefficient	Instability index	Aliphatic index	GRAVY
EGFR	460	50,343.70	7.10	49	49	38,305	35.56	72.91	–0.269
KRAS	180	21,470.62	8.18	29	31	12,170	43.95	77.18	–0.559
TP53	340	38,532.60	5.64	41	33	43,025	80.17	63.99	–0.592

Furthermore, the structure and function of the protein can be affected by salt bridges. Thus, salt bridge disruption minimizes the stability of protein [26]. Next, it is also associated with regulation, molecular recognition, oligomerization, flexibility, domain motions, and thermostability [27, 28].

The greater number of arginine in the protein model enhances the stability of the protein. This is happens through the electrostatic interactions between their guanidine group [29]. Hence, it was confirmed that all the protein models are in the identical stable conditions. The outcome of Cys_ Recserver exhibits that the quantity of disulfide bonds in EGFR is 42, K-ras oncogene protein is 5, and TP53 is 11 (Table 1.2).