XFEL Crystal Structures of Peroxidase Compound II.

Oxygen activation in all heme enzymes requires the formation of high oxidation states of iron, usually referred to as ferryl heme. There are two known intermediates: Compound I and Compound II. The nature of the ferryl heme-and whether it is an FeIV =O or FeIV -OH species-is important for controlling reactivity across groups of heme enzymes. The most recent evidence for Compound I indicates that the ferryl heme is an unprotonated FeIV =O species. For Compound II, the nature of the ferryl heme is not unambiguously established. Here, we report 1.06 Šand 1.50 Šcrystal structures for Compound II intermediates in cytochrome c peroxidase (CcP) and ascorbate peroxidase (APX), collected using the X-ray free electron laser at SACLA. The structures reveal differences between the two peroxidases. The iron-oxygen bond length in CcP (1.76 Å) is notably shorter than in APX (1.87 Å). The results indicate that the ferryl species is finely tuned across Compound I and Compound II species in closely related peroxidase enzymes. We propose that this fine-tuning is linked to the functional need for proton delivery to the heme.

The Prevalence of Risk Factors for Cardiovascular Diseases in Najran Region, Saudi Arabia.

The primary goal of this study was to investigate the knowledge, prevalence, and risk factors of cardiovascular diseases among individuals in the Najran region of Saudi Arabia. In the Najran region of Saudi Arabia, an online cross-sectional survey was conducted. Between September and October 2023, a self-administered questionnaire was distributed to a random sample of the general population aged 18 and up. The survey instrument asked about history and exposure, physician-diagnosed illnesses, cardiovascular diseases (CVDs), medication use, and other risk factors. This research had a total of 2046 individuals. Around one-fifth of the study participants reported that they or a family member suffered from CVD, and arrhythmia was the most commonly reported; blood tests, cardiac catheterization, and ECG were the most commonly reported tests performed for CVD patients, around one-tenth of CVD patients reported that they do not have any chronic diseases other than CVD, and the vast majority of the patients confirmed their regular medical appointments. This is one of the first studies to investigate the knowledge, prevalence, and use of CVD drugs among individuals in the Najran region of Saudi Arabia. The study participants' lack of knowledge about CVD could lead to ineffective preventive measures and poor patient outcomes. The study's findings underscore the crucial need for more extensive and efficient educational initiatives that consider the targeted population's talents, attitudes, and perceptions.

XFEL Crystal Structures of Peroxidase Compound II.

Oxygen activation in all heme enzymes requires the formation of high oxidation states of iron, usually referred to as ferryl heme. There are two known intermediates: Compound I and Compound II. The nature of the ferryl heme-and whether it is an FeIV=O or FeIV-OH species-is important for controlling reactivity across groups of heme enzymes. The most recent evidence for Compound I indicates that the ferryl heme is an unprotonated FeIV=O species. For Compound II, the nature of the ferryl heme is not unambiguously established. Here, we report 1.06 Šand 1.50 Šcrystal structures for Compound II intermediates in cytochrome c peroxidase (CcP) and ascorbate peroxidase (APX), collected using the X-ray free electron laser at SACLA. The structures reveal differences between the two peroxidases. The iron-oxygen bond length in CcP (1.76 Å) is notably shorter than in APX (1.87 Å). The results indicate that the ferryl species is finely tuned across Compound I and Compound II species in closely related peroxidase enzymes. We propose that this fine-tuning is linked to the functional need for proton delivery to the heme.