The catalytic inactivation of the N-half of human hexokinase 2 and structural and biochemical characterization of its mitochondrial conformation

Mir Hussain Nawaz, Juliana C. Ferreira, Lyudmila Nedyalkova, Haizhong Zhu, César Carrasco-López, Serdal Kirmizialtin, Wael Rabeh

Research output: Contribution to journalArticle

Abstract

The high proliferation rate of tumor cells demands high energy and metabolites that are sustained by a high glycolytic flux known as the ‘Warburg effect’. The activation and further metabolism of glucose is initiated by hexokinase, a focal point of metabolic regulation. The human hexokinase 2 (HK2) is overexpressed in all aggressive tumors and predominantly found on the outer mitochondrial membrane, where interactions through its N-terminus initiates and maintains tumorigenesis. Here, we report the structure of HK2 in complex with glucose and glucose-6-phosphate (G6P). Structural and biochemical characterization of the mitochondrial conformation reveals higher conformational stability and slow protein unfolding rate (ku) compared with the cytosolic conformation. Despite the active site similarity of all human hexokinases, the N-domain of HK2 is catalytically active but not in hexokinase 1 and 3. Helix-α13 that protrudes out of the N-domain to link it to the C-domain of HK2 is found to be important in maintaining the catalytic activity of the N-half. In addition, the N-domain of HK2 regulates the stability of the whole enzyme in contrast with the C-domain. Glucose binding enhanced the stability of the wild-type (WT) enzyme and the single mutant D657A of the C-domain, but it did not increase the stability of the D209A mutant of the N-domain. The interaction of HK2 with the mitochondria through its N-half is proposed to facilitate higher stability on the mitochondria. The identification of structural and biochemical differences between HK2 and other human hexokinase isozymes could potentially be used in the development of new anticancer therapies.

Original languageEnglish (US)
Article numberBSR20171666
JournalBioscience Reports
Volume38
Issue number1
DOIs
StatePublished - Feb 21 2018

Fingerprint

Hexokinase
Conformations
Enzyme Stability
Glucose
Mitochondria
Protein Unfolding
Tumors
Glucose-6-Phosphate
human hexokinase 2
Mitochondrial Membranes
Isoenzymes
Catalytic Domain
Neoplasms
Carcinogenesis
Enzymes
Metabolites
Metabolism
Catalyst activity
Chemical activation
Cells

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Cell Biology

Cite this

The catalytic inactivation of the N-half of human hexokinase 2 and structural and biochemical characterization of its mitochondrial conformation. / Nawaz, Mir Hussain; Ferreira, Juliana C.; Nedyalkova, Lyudmila; Zhu, Haizhong; Carrasco-López, César; Kirmizialtin, Serdal; Rabeh, Wael.

In: Bioscience Reports, Vol. 38, No. 1, BSR20171666, 21.02.2018.

Research output: Contribution to journalArticle

Nawaz, Mir Hussain ; Ferreira, Juliana C. ; Nedyalkova, Lyudmila ; Zhu, Haizhong ; Carrasco-López, César ; Kirmizialtin, Serdal ; Rabeh, Wael. / The catalytic inactivation of the N-half of human hexokinase 2 and structural and biochemical characterization of its mitochondrial conformation. In: Bioscience Reports. 2018 ; Vol. 38, No. 1.
@article{8f8071af43de4313805798a94f202e3f,
title = "The catalytic inactivation of the N-half of human hexokinase 2 and structural and biochemical characterization of its mitochondrial conformation",
abstract = "The high proliferation rate of tumor cells demands high energy and metabolites that are sustained by a high glycolytic flux known as the ‘Warburg effect’. The activation and further metabolism of glucose is initiated by hexokinase, a focal point of metabolic regulation. The human hexokinase 2 (HK2) is overexpressed in all aggressive tumors and predominantly found on the outer mitochondrial membrane, where interactions through its N-terminus initiates and maintains tumorigenesis. Here, we report the structure of HK2 in complex with glucose and glucose-6-phosphate (G6P). Structural and biochemical characterization of the mitochondrial conformation reveals higher conformational stability and slow protein unfolding rate (ku) compared with the cytosolic conformation. Despite the active site similarity of all human hexokinases, the N-domain of HK2 is catalytically active but not in hexokinase 1 and 3. Helix-α13 that protrudes out of the N-domain to link it to the C-domain of HK2 is found to be important in maintaining the catalytic activity of the N-half. In addition, the N-domain of HK2 regulates the stability of the whole enzyme in contrast with the C-domain. Glucose binding enhanced the stability of the wild-type (WT) enzyme and the single mutant D657A of the C-domain, but it did not increase the stability of the D209A mutant of the N-domain. The interaction of HK2 with the mitochondria through its N-half is proposed to facilitate higher stability on the mitochondria. The identification of structural and biochemical differences between HK2 and other human hexokinase isozymes could potentially be used in the development of new anticancer therapies.",
author = "Nawaz, {Mir Hussain} and Ferreira, {Juliana C.} and Lyudmila Nedyalkova and Haizhong Zhu and C{\'e}sar Carrasco-L{\'o}pez and Serdal Kirmizialtin and Wael Rabeh",
year = "2018",
month = "2",
day = "21",
doi = "10.1042/BSR20171666",
language = "English (US)",
volume = "38",
journal = "Bioscience Reports",
issn = "0144-8463",
publisher = "Portland Press Ltd.",
number = "1",

}

TY - JOUR

T1 - The catalytic inactivation of the N-half of human hexokinase 2 and structural and biochemical characterization of its mitochondrial conformation

AU - Nawaz, Mir Hussain

AU - Ferreira, Juliana C.

AU - Nedyalkova, Lyudmila

AU - Zhu, Haizhong

AU - Carrasco-López, César

AU - Kirmizialtin, Serdal

AU - Rabeh, Wael

PY - 2018/2/21

Y1 - 2018/2/21

N2 - The high proliferation rate of tumor cells demands high energy and metabolites that are sustained by a high glycolytic flux known as the ‘Warburg effect’. The activation and further metabolism of glucose is initiated by hexokinase, a focal point of metabolic regulation. The human hexokinase 2 (HK2) is overexpressed in all aggressive tumors and predominantly found on the outer mitochondrial membrane, where interactions through its N-terminus initiates and maintains tumorigenesis. Here, we report the structure of HK2 in complex with glucose and glucose-6-phosphate (G6P). Structural and biochemical characterization of the mitochondrial conformation reveals higher conformational stability and slow protein unfolding rate (ku) compared with the cytosolic conformation. Despite the active site similarity of all human hexokinases, the N-domain of HK2 is catalytically active but not in hexokinase 1 and 3. Helix-α13 that protrudes out of the N-domain to link it to the C-domain of HK2 is found to be important in maintaining the catalytic activity of the N-half. In addition, the N-domain of HK2 regulates the stability of the whole enzyme in contrast with the C-domain. Glucose binding enhanced the stability of the wild-type (WT) enzyme and the single mutant D657A of the C-domain, but it did not increase the stability of the D209A mutant of the N-domain. The interaction of HK2 with the mitochondria through its N-half is proposed to facilitate higher stability on the mitochondria. The identification of structural and biochemical differences between HK2 and other human hexokinase isozymes could potentially be used in the development of new anticancer therapies.

AB - The high proliferation rate of tumor cells demands high energy and metabolites that are sustained by a high glycolytic flux known as the ‘Warburg effect’. The activation and further metabolism of glucose is initiated by hexokinase, a focal point of metabolic regulation. The human hexokinase 2 (HK2) is overexpressed in all aggressive tumors and predominantly found on the outer mitochondrial membrane, where interactions through its N-terminus initiates and maintains tumorigenesis. Here, we report the structure of HK2 in complex with glucose and glucose-6-phosphate (G6P). Structural and biochemical characterization of the mitochondrial conformation reveals higher conformational stability and slow protein unfolding rate (ku) compared with the cytosolic conformation. Despite the active site similarity of all human hexokinases, the N-domain of HK2 is catalytically active but not in hexokinase 1 and 3. Helix-α13 that protrudes out of the N-domain to link it to the C-domain of HK2 is found to be important in maintaining the catalytic activity of the N-half. In addition, the N-domain of HK2 regulates the stability of the whole enzyme in contrast with the C-domain. Glucose binding enhanced the stability of the wild-type (WT) enzyme and the single mutant D657A of the C-domain, but it did not increase the stability of the D209A mutant of the N-domain. The interaction of HK2 with the mitochondria through its N-half is proposed to facilitate higher stability on the mitochondria. The identification of structural and biochemical differences between HK2 and other human hexokinase isozymes could potentially be used in the development of new anticancer therapies.

UR - http://www.scopus.com/inward/record.url?scp=85043278019&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85043278019&partnerID=8YFLogxK

U2 - 10.1042/BSR20171666

DO - 10.1042/BSR20171666

M3 - Article

VL - 38

JO - Bioscience Reports

JF - Bioscience Reports

SN - 0144-8463

IS - 1

M1 - BSR20171666

ER -